While I'm back in the UK I'm going to build a custom bike ( chopper ) to bring back with me which should be a right laugh to homologate. It'll still be cheaper than buying a bike here though.
I can think of ways around the 6 month rule, but I'm going to keep them to myself

I might need them
I'm in two minds about all these bullshit regulations involving vehicles. There is a safety aspect, but mostly it's just an excuse for governments to fleece you out of your money so they can spend it on their own expense accounts, give it to people who don't work or just generally waste it on a load of crap. They justify their thievery by saying it's saving the planet or the children or something like that.
Having had two cars written off and one badly damaged in the UK by uninsured drivers who didn't stop I can see the justification in laws making insurance compulsary though.
Also, why do the Spanish make the homologation process so difficult and expensive ? is it going to cause millions to die if you have sidesteps on your 4x4 or different tyres than the manufacturer originally installed ? Of course it isn't - it's just bureacracy for the sake of it, sheer stupidity.
If they want to make a major contribution to road safety they would be better off teaching the indigeneous population how to drive properly. It only has to rain and the daft buggers are arse-ending each other left right and centre. Most of them drive like 80 year old women, can't park to save their lives and the number of Spanish vehicles with major dents and scrawks is mind boggling