Doesnt need to be portable- really just for locking a bike in a shed- even threading steel weight training weights through as well (or attaching using another cable onto).

if its for a shed try this

http://www.torc-anchors.com/products.php?cat=18

they have other stuff for garages etc

Go for the motorbike stuff:

http://www.motorcyclenews.com/upload/Ride%20Magazine/Product%20test%20pdfs/8%20AUG08%20Lock&chain%20test.pdf

The Oxford XL Hardcore and Oxford Monster came top, both £50 and stocked all over the place. Fit a ground anchor too and you're set.

put bingo in the shed!

look at motorbike locks!!

Motorcycle locks – d locks are best followed by chain and padlock with cable locks a poor third. £50 is the absolute minimum for a decent lock and be prepared to pay more.

Abus magnum are good as are the top of the range oxford stuff

Oxford- check. Off down to my local motorbike store. ta guys.