Hi guys, really appreciate you suggestions on this.
Was doing the same prior to coolant change, followed the book and bled the system, all ok, checked again after run still fine.
It was ok prior to not using it much last year.
Had the rad off all ok so I'm doing the rad cap as I see that a lot on bb forums, maybe thermostat if not I guess water pump is next but from what I read the failure rate on them is small.
Brill bike and love being part of this community even if it starts with a problem lol