hello Tony , sorry for late update, had a look inside throttle body - all the gears are ok and moving fine but there was quite a bit of oil inside . I thought there was nothing to loose by trying to clean with brake cleaner so did this and reassembled but intermittent problem still there.
next called a KIA dealer for price & availability of throttle body and was told this isn't available on its own but comes with the inlet manifold at £866 !
unsurprisingly the owner doesn't want to spend this much on a part

any ideas for an alternative source of a throttle body would be helpful,
thanks