Just to let you know,the choke mech in the carb was well and truly seized in, and despite my efforts and copious amounts of wd40 i finally had to resort to handing it to those nice folks at Moto Strada in Shipley,west yorks to sort. two and a half hours labour later and it's now unseized and working perfectly.
They also cleaned the carb out, it runs sweet as a nut now, with a delightfull 'pop and burble' on the overrun through the scorpion pipe
Lesson learned,the bike was 'stood' for 18months before i bought it,they obviously don't like old gas being left in the carb!
Thanks to all who offered advice.
Ian