I want to get a long sleeve merino riding top for autumn (think it would be good for bb200). Would like something a little heavier weight than the base layers mostly available in merino.

Looking at on-one they seem seem good tops for the money - anyone got one?

Also any other bargains out there to investigate?

Indeed a real bargain, mine are the best of all the merino I have (Finnistere & Endura) worked really well for years, come up fine from washing etc..

Yes the stuff from On-one is good ... even if it were twice as much it would still be a good deal.