£5 per person is steep, in my experience.
'The Cross' in Charing Cross (very central london) charge £2 per table.
Central London Wargamers (Euston) charge nothing.*
The Perseverence (Paddington) charge nothing.*
*Though you are expected to buy a drink or two at the bar.
Well, even when I used to go to clubs in Milton Keynes and Northampton sixteen or seventeen years ago they charged £2-3 per person to play. If a club has no form of income, then even if there is no rent to pay then it will never be able to get beyond the 'bring it yourself' stage, and getting new boards, etc... will rely in effect on some members to subsidise the rest of the club by donating them themselves, etc... As of course your normal function table is 3'x6', just about the wrong size for most games...
Likewise the only club I've regularly frequented in London, Tanelorn charges IIRC £4-6 per evening. They are in financial difficulties at the moment though, due of course to high rents and attendance numbers that can't support those rents, so they are looking to move to a cheaper venue, unfortunately for me even further East around the A406...
Wednesdays are probably good, as GW Wood Green recently stopped opening late nights on a Wednesday there may be some interest from there.
Well, Finchley is almost equidistant from Brent Cross and Wood Green, and has pretty good transport links by bus and tube. Plus there are several large schools in the immediate area of the venue I'm looking at. So whilst the central London clubs obviously cater for those that work in central London, I am aiming much more towards attracting regular attendees from the local area, and perhaps as far west as Wembley and beyond for those who drive. But of course I'd be looking for a great deal of the advertising and potential members for the club to come from the 'regulars' of these two GW stores, be they teenagers or grumpy old men like me, etc...
Have you tried asking pubs if they're willing to let a spare room upstairs be used for free, on condition that the gamers buy a drink or two?
You did mention kids though, so maybe that's a non-starter.
Well, I think that the central London clubs cater for the adult gamers that work in town and don't mind playing in a cramped function room and having a few pints. So looking for free function rooms in pubs (as far as I am aware there are no pubs in Finchley with separate function rooms, well there might be one but I'd rather not cross its threshold...) would merely be replicating these but in the suburbs. It also ties you very specifically to that venue and does of course as you say, limit your members to adults I guess, although IIRC 16 year olds can go into a pub, they just can't buy anything more than a soft drink. But as I'm sure you all know, many wargamers tend to pick up the new hobby of 'beer and girls' around the age of 16, and only a select few come back to the hobby when they are 21+... It also ensures that you will be very, very unlikely to be able to do a weekend club meeting, or of course organise events there, etc...
That's the theory anyway... Of course if we can get 20+ people to turn up regularly, then table rates can go down. Another way to reduce costs is to reduce the hall hire time. So if you are being charged £10hr, and you expect ten people, then rather than doing 6-11, or 5:30-10:30, you could do 6-10, or even really pushing it for 7-10. But personally I'd rather have a longer club night to allow for either two quick games, or one big or slow game... Heck in 5hrs you could do four or maybe even six Space Hulk missions once both players know what they're doing...
I know that the demand is there. During the summer some of the regulars at BX tried to set up a club in the Borders store across the A406, but being tied to the 9pm store closing time meant that it would have excluded most adults that worked, and of course myself as my wife often gets home around 7-8pm (I'm likely to have to pay a babysitter to be able to go to this club when it's set up). But the guys that were trying to set it up were IIRC students and teachers, so when the holidays finished suddenly they didn't have the time to set it up any more...
Anyway, enough waffling for the time being...