There's a simple rule that I use when I'm reviewing a restaurant; the more expensive it is, the higher the standards that I apply when assessing it. This seems entirely reasonable to me, as value for money has to come into the equation somewhere. Besides which, if you're going to spend a lump of hard-earned cash, it's makes for a better evening if you feel good about it afterwards. So if what follows is pickier than usual, that's because the meal cost more than usual.

I was taking Gill Hall to dinner, and on the couple of previous occasions that she has accompanied me, we haven't always hit lucky. So this time I was determined to go somewhere that a good meal would be virtually guaranteed and picked out Barberstown Castle. It had the further advantage of being outside the city, which seemed a nicer place to be on a summer's evening. I'd booked a table for Gill Hall at 8.30, but what with the taxi arriving late and heavy traffic as well it looked like we wouldn't be on time. I phoned Barberstown to tell them that it would be nine before we arrived and was told that that was no problem.

Arriving bang on 9 o'clock we found a series of car parks, all filled pretty much to capacity. Barberstown Castle is a big place, although as Gill wryly remarked, about 90% of it is the extension. The castle itself, recognisable as the only part of the buildings in stone, seems to be a keep, and takes up position in a corner between the various other buildings. Immediately inside the front door there's a hall with a reception counter, and on either side of that there are sitting areas. We were shown into the one on the left where a piano-player was hard at work and where a bar has been carved out of the adjoining room. It's full-blown Victoriana in here; a large ormolu overmantel mirror and others on the walls; green wallpaper, dark carpet and upholstered Edwardian chairs and chaises longues. I asked Gill what she thought of the swaggings and festoons, since textile design and fabrication is what she does. 'Well, it's certainly expensive,' was her considered response.

This is the sort of place that likes you to sit in the bar, look at menus, make your choices and then come to the dining room when called. I operated a similar system myself when I had a restaurant, so I've no objections in principle. There's two menus to choose from, a tasting menu at £42.50 per person, (a bargain that's only available if all members of a party choose it) or an a la carte. There are some interesting starters on the menu: rosemary prawn kebabs at £12.50, crispy smoked quail and chicken wontons at £9.00, terrine of foie gras and fresh figs at £13.50, asparagus salad with lambs sweetbreads at £9.50, a pave of sea bass at £9.00, and tian of avocado, goats cheese and soft-boiled quails egg at £8.50. If you were feeling hungry there's an intermediate course with a choice of soup or sorbet, before the listing of main courses. Grilled turbot £22, loin of veal £21, baked John Dory fillets with pan-fried oysters cabbage and celeriac £19, confit of roast Greshingham duck £19.50, steamed paupiettes of Dover sole £23.50 and fresh lobster with vanilla butter sauce at £32.50. A selection of vegetables to add to these dishes is an additional £5.

I turned to the wine list. Like the menu, it's not cheap. It's almost entirely a French listing, so if you're big into New World wines you won't find any here. It begins, traditionally enough, with a listing of Bordeaux. Here are a few samples: Ch. Palmer1990 £145, les Ormes de Pez 1995 £49, Ch. Giscours 1995 £78, Phelan Segur 1996 £59. Burgundies follow much the same road; Aloxe Corton 1996 £79, Fleurie £27, Macon Lugny £22. After the white burgundies there are listings for the Loire, Rhone and Alsace. I found three Italians, an Amarone at £42, a Barolo at £48 and a plain, humble Frascati for £20. As a wine list it puzzled me. What's the point of weighting a list so heavily towards expensive French wines? Can it be simply that a high mark up is more easily obtained? Certainly £20 for a Frascati is pushing the limits of acceptability. In the end I picked the Macon Lugny, which at £22 is about £5 over the odds.

Forty-five minutes after we'd arrived we were summoned to the dining room. Perhaps I needn't have bothered phoning to say we'd be half an hour late. There seemed to be three dining rooms downstairs, ours was the ground floor of the keep itself, so it was high-ceilinged with stone walls. These walls were decorated with the taxidermist's art; heads of all kinds of animals looked out at we diners with their fixed, glassy eyes. 'Maybe the rest of them got eaten here,' said vegetarian Gill, shuddering. A big table was ours to sit at, and our starters arrived after another ten minutes - prawn kebabs for Gill and avocado tian for me. Both of these were very good, but I'll confess that for a moment I thought my dainty tian was an amuse bouche, rather than my starter.

Gill had picked the turbot for her main course and I'd chosen the John Dory. Both of these dishes were good and competently prepared. The vegetables that were priced at £5 included deliciously spiced carrots - for which Gill wanted the recipe - plain mange-tout and badly-cooked roast potatoes. The small leaf salad - also £5 - had a dressing unpalatable to me, so I left it, but the cabbage and celeriac that accompanied my fish was exquisite. Quite a mix of excellent and pedestrian.

After this we wanted a cigarette before desserts, but this is a non-smoking dining room, so we went back to the bar where our waitress served us our desserts; a rich dark chocolate tart for Gill and an iced lemon and orange mousse for me, both listed at £7.50. No espressos were available, so we settled for two cognacs instead. The bill came to £121.50 not including service. As we left I wondered who is this aimed at? Gourmets will pay that and more for faultless food, but ours was a little uneven. Is it for people who like dining in castles? Possibly. On balance we'd eaten well, the service had been attentive, but the gaps between courses were inordinately long. It was the classic curate's egg: good in parts.