not sure, a one bedroom flat is ok for 2 of you, what's probably best to show when applying for any visa is stability, relationship,job/income and accommondation.
if he's been renting for years and then you mention that you will be renting from a friend, will his friend give him a proper rent agreement/rent book ??
i would keep things simple as possible, simpler the app the better, bit like scouser keith(admin guy)
me personally i wouldn't mention it, but who knows..![]()