Contents insurance?

I am renting a new build lock up. Its large garage sized and is obviously covered by the owner but I was thinking the collective amount of tools and equipment stored in there is going to be around the ten thousand pounds mark so im thinking of trying to insure contents.
Its not commercial, just DIY and tinkering space but I have collected some expensive gear over the years and would rather be covered. The built security is pretty good with solid steel doors and good quality mortise locks but there is no electric apart from a diesel generator that is wheeled outside when working on anything.
Any ideas who I should get quotes from or indeed if such cover exists.

Don't think that's an uncommon insurance. Not needed it myself but there must be plenty that do and of course you need something not just for contents but buildings and liability to others (fire spread, etc.)
Its the what if test. What if your car went on fire and the fire spread to neighbouring lock-up and killed his Bentley Continental whilst it was being refurbed?
Did a quick internet trawl and a good number of insurers came up.