In short the NPPL banned them following discussions with insurrance companies then the Brits followed suit....
the reason given here was that turbo in the amount of shots per trigger pull was "just" the right side of the law so to err on the side of caution we banned their use.
If you have the newer LS board it is quicker than the old one so add a Blade trigger or if you have lots of money get a Hypersports frame and you will have a really fast marker even with the Turbo switched off, I did exactly the same thing and didn't notice a difference in the rate of fire. If you have the old board ie dome switch you don't have a lot of choice, you will have to get a Hypersports Frame.
Hope this helps.