Here's a link to the UK LASORS, you should look for G1.5.
http://www.caa.co.uk/docs/175/Sectio...%20LICENCE.pdf
In a nutshell, unless you have more than 3.000 hours/ 1.500 PIC in +30.000 kg public transport you will need to do all 14 ATPL written exams, plus the Flight Skills Test.
PM me if you want and I'll try to give you as much info as I can; did the whole thing a couple years ago.
Cheers.