I have a Masterlock Street Fortum D lock. It's Sold Secure Gold rated and cheap. You can get it for under £30 including a cable loop for the front wheel. I put my two bikes on my house contents insurance as well. £1500 of cover for £22 pa. Unlike some expensive bike-specific insurance policies, they don't specify a security rating and they don't have ludicrous weasel get-out clauses in the small print.
BTW, the Evolution Mini can sometimes be a bit small if you want to lock your frame and wheel to a chunky piece of street furniture.