Many thanks for all your replies.
This is my first new lens purchase since 2008 (bought many s/h lens though).

Just got one (delivery this afternoon) in the Black Friday offers, certainly a beast compared to my other 400mm and 500mm film lens

Just treated myself to a HD Dfa 150-450 not be able to find a Ricoh site to register my purchase (found the USA one very easy but does not accept uk address)