A quick update:
There have been a few responses from the companies I sent emails to. Some unsurprising silences and some surprising silences. I guess their view is "well, we're getting a mention for free anyway so why bother paying"

Each to his own...
Those who have responded (thanks!) will get a small sponsored banner at the top of the page, to the right of the logo.

I'll probably turn this on this evening but there will only be one banner there until I can get the others loaded.
Sponsored companies will also get a special section to post new things in the "for sale" section.
The adverts:
As has been noticed, I have started trying out Google adwords for those who are not logged in. I'm trying to get the criteria correct so it mostly shows relevant ads. When I first started putting it on it was showing me Muslim dating sites.
It is now mostly showing relevant stuff but it's a WIP.
I'll also be putting in the google adverts into the main forum as well with and option to turn them off

. An annual donation of £12 clears all the adverts from the site (but not the sponsored banner at the top)
They won't be too loud and obnoxious but they will be there and once turned off they'll vanish like oil from a Dutsan.
Things are moving along and I am getting to adding the bits in and trying out a few things. The keen eye might have spotted that I
totally broke the forum a few days ago.. After clicking apply I started getting hundreds of emails about errors. Whoops

I'll get the rest of the bits sorted out in the coming days and turned on. Time is a bit tight for me with other work so this really is a "work at night" task at the moment.
I think the options laid out are a good mix and while I know I can never make everyone happy all the time, I can only try and make most of the people happy most of the time.
Cheers,
CP