Secure Motorcycle garage in London?

[Socks]

Tentative inquiry. I am unsure that this post should be in this section, but it is related.
First let me explain, I have two bikes, the first is an everyday use bike and the XT 3aj, which is a project, yet used bike, and therefore is used as and when. Here is the problem (as most of you will be aware) living in East London with a M/bike, particularly an xt, the low life that see such a bike appear to believe it is their right to have it for themselves (two stolen previously). I have no garage to do work on the bike, which means I have to carry my tools up and down to 4th floor from the exposed communal yard where I live.
The inquiry is, I require a safe place to store and work on my XT.
Storage facilities are not cheap and most don’t allow maintenance to be carried out.
I am thinking that there are more of you here on the HUBB (some) in East London, in a similar situation, and might consider a shared secure lock up?
My trade as a gardener and many years of doing my own M/C maintenance may be of interest, as I could return my knowledge/ time in exchange for a garage.
I am inviting (almost!) any ideas on this.
Regards
Socks