Thanks for your responses all..appreciated.
I took it to a local tyre place, got all 4 tyres changed (part-worn), i found out that one of the front tyre was badly worn and the other had plenty of thread (assume previous owner replaced one with brand new and left the other)
So, once i got the tyres replaced, took it for a spin and the problem has gone! I've got a long journey to do this weekend so will be able to tell 100% if its cured.
Fingers crossed 🙂