With no power in the garage it seemed like a good idea. Proof in the pudding will be on Saturday when I wheel the bike out and hope to have some charge to get it started!
The one on the Maplin site now is slightly upmarket compared with mine that cost £9.99 as it has a choice of connector, fag lighter plug and crocodile clips; when mine came only with a fag lighter plug. The new £14.99 version comes suction caps to mount it with. I have mine on a pile of bricks outside my garage door and the wire trailing to the bike inside. As it doesn't look too waterproof I have it in a tasteful clear placcy bag.