If there's an establishment with more genuine old-school hospitality in the country than Ashford Castle in Cong, Co Mayo, then I've yet to visit it. Much of this, of course, has to do with the length of service many of the staff have put in – almost 40 have been there for over 10 years and several for more than 30. It makes for a warm welcome, and explains why a regular stay at Ashford, which dates from the 13th century and is celebrating its 70th anniversary as a hotel this year, is a tradition for so many well-heeled families. Like every other hotel in the country, though, Ashford can't afford to sit back, rest on its laurels and wait for the guests to come regardless. It is currently offering some very good and accessible deals, with the result that it was fully occupied on a recent weekend with a mix of family groups and couples of all ages.

The Dungeon Bar offers informal dining, of which reports are good, but dinner in the George V Dining Room is definitely an occasion. Men are "required" to wear a jacket and "requested" to wear a tie – in practice this means jacket only. Women make an effort and the imposing room, dripping with chandeliers, deserves and repays the compliment.

For all the rather old-fashioned palaver that accompanied the process of being seated and settled in to our window table, the service was friendly rather than stiff, and the ambience cosseting rather than stuffy. The staff – from chirpy Maitre d' Martin Gibbons, with 32 years behind him, down to the younger and no less cheerful international waiters – were, without exception, efficient and attentive.

The Table d'Hote menu is €75 a head. Helpfully, the menu suggests wines available by the glass to accompany each course – a great idea that I'd like to see copied in more restaurants as it's ideal for a couple in particular when the dishes chosen would not suit the same choice of wines and two bottles would be over-doing it. We started with a perfectly judged amuse of leek quiche topped with a sliver of smoked salmon and followed with starters of Bluebell Falls goats' cheese (a mixed presentation of warm and chilled preparations of this local cheese) and roast fillet of local venison served with a chilled mousse of salsify and truffles, served medium-rare. The goats' cheese was good without being exceptional, and suffered from being rather over-shadowed by the superb venison, so tender and flavoursome that we fought over the not ungenerous portion and wished we could have ordered it as a main course.

Instead, we opted for roast rack and braised shoulder of local lamb served with goats' cheese potato pasta and sautéed beans, and fresh Atlantic seafood served in a broth of vegetables and herbs. The lamb was terrific, full of flavour, and the single gnocchi a successful counterpoint to the meat. The composition of the seafood dish changes according to what's freshest in the market on the day – we got organic salmon, monkfish, cod and mussels – in an intensely saffron-flavoured broth. We liked it very much, but thought that the menu should have mentioned that saffron was the dominant flavour as it is not universally popular.

Crème brulée of chestnuts with blackberry sorbet was served in a shallow wide dish to maximise the surface area of burned crispy topping that is the real reason anyone orders the dish – top marks! From an Irish farmhouse cheese menu which intelligently graduates the descriptions of the cheeses on offer from the mildest to the strongest we chose Hegarty's cheddar, an organic Mossfield gouda, a terrific Crozier blue and a punchy raw cows' milk Bellingham blue. The cheeses were all in excellent condition and we didn't mind the xenophobia – or was it patriotism? – of the offering one bit.

We were guests on this occasion, but at €75 a head, with generous glasses of the selected wines ranging from €10 to €20, the dinner menu is fairly priced for the quality of the food and the opportunity to experience fine dining in the extraordinary surroundings of Ashford Castle. Perfect for a special celebration.

Ashford Castle

Cong, Co Mayo

T: 094 9546003

Rating: 4/5