I presume you've checked it's got the right grade of oil in there ?

Too thick an oil will most definitely help to create stiction between the plates.

As already stated already it'll take a while of riding and warming up before they release.

At least you know the box is working okay

 

 

thanks for the response for the clutch side I've got 

weastway SAE30

and for the gearbox

westway 80w90 gear oil

been told 300cc in each does this sound right 

thanks

From (distant) memory, clutch was 250cc and gearbox 550 but someone will know exactly.  I think you could do better than a 30 in the clutch, given modern oils.