Thanks, I raised an incident with Arturia shortly after my post here and I have just received an email suggesting the same thing, i.e. delete the prefs files, which has worked.
Thanks for your help.
EDIT: forgot to say, yes, these are an absolutely amazing collection of synths. I think the only one which lets the side down a bit is the CS80. The version in V Collection 5 has of course had a much needed cosmetic makeover but the sound engine behind the scenes needs a re-think IMO, it is not as close to sounding like a real CS80 as the Memory Moon ME80, which in comparison looks amateurish but sounds better. I've been hugely fortunate in having used a real CS80 and most of the panel presets on the Arturia version are a mile away from sounding correct.