Marquees are stupendously expensive - IME a marquee will cost more than a hotel unless you have it at home and have a free bar, in which case the cost of buying the booze and paying for the marquee will probably be less than the cost of paying for the bar at a hotel...
We had our reception at the local town hall. Hire cost was £500 and we could use any caterer. We had to use their bar but it was only £3 a bottle corkage (including service and glasses) so we took our own wine. We paid for all drinks at the bar too.
I think our catering was £17.50 a head for 3 course dinner - starter choice of soup or prawn cocktail, served to table then main course hot buffet with choice of sausage & mash or chicken curry & rice plus chips for everyone (plus choice of veggie sausages and vegetable curry), then pudding served to table choice of choc orange pudding, fresh strawberries, raspberry pavlova or fruit salad. Evening buffet was £7.50 a head for the 'basics' sausage rolls, sandwiches etc - nothing fancy, but plenty of food.
We bought 8 cases of wine from M&S (96 bottles in total) which was about £600, plus corkage for the ones opened (£3 x 60 =£180).
We paid for the bar drinks, which was about £550 as most people drank the wine anyway. We stipulated single measure spirits only, no doubles or cocktails but otherwise free bar all day and night.
So for 86 people it cost:
Venue £500
Catering £25 a head £2,150
Drink £1,330
We also had a band, which was expensive. A friend made the cake. We provided transport for guests and the florist made centrepieces for the tables, but all this is optional of course.
The local council don't advertise that the town hall is for hire, I just rang up and asked because I was desperate!