I'd go for the wall and biggest bolts u can use. There is a bonding agent u can get to proper set the bolts in even if there the expanding type. Make sure it's high enough so the chain your using doesn't touch the ground. Preferably a smallish one so the scumbags can't just move the bike nearer. This is the best chain money can buy and it lasts a lifetime.
http://youtu.be/paNzJslXGkM
Seriously ....,.these are the best
http://www.almax-security-chains.co.uk
http://youtu.be/paNzJslXGkM
Seriously ....,.these are the best
http://www.almax-security-chains.co.uk
Just flapping about on this stagnant little pond on the outer rim of the internet.....yup.... :-))