B & Q !!!
There's nothing stopping Home Depot setting up themselves here, they might have to change their logo for the UK though because it's too similar to B&Q's!

Why didn't they buy up the Focus DIY chain when that went into admin? That would have given them a start.
I'm thinking you are being ironic in calling B&Q idiots for rejecting the approach, it's a big company that is doing well and turning a nice profit, why would the shareholders want to sell up? Home Depot sell the same stuff as B&Q so I'm not sure why you'd specifically want them to run it instead.