Thanks, I'll update it
HiNice looking bike, bit difficult to ID, could do with close ups of the lug work and rear brake bridge. Holdsworth used 4 digit numbers in the early 60's and seemed to again in early 70's. For numbers below 1000 there were 3 digit without a leading zero, so I assume this is from one of these groups. Your bike looks 70's or even 80's, but if 80's it would have the Holdsworth 6 digit number. So I am thinking if it has a straight brake bridge it might be from the 70's group. As this group ran in parallel with the std factory 5 digit system it seems to be used for contract builds by Holdsworth for other firms/shops or under licence builds of Holdworth frames by other shops. there were several number systems in the early 70's that all got replaced by the std. 6 digit system in 1976, see attached chart. The location of the number is different to most 70's 4 digit numbers I have seen, but may not be significant.
As for the model I don't think this is a Mistral as that model had distinctive head lugs which look different to yours. It also had a wrap over seat stay attachment, until later in 80's, which I can't see clearly in your picture. That said the super did have a similar fork crown. I have attached some details all of which can be seen here. http://nkilgariff.com/HoldsModelPages/Mistral.htm & http://nkilgariff.com/Models.htm. Also most of the factory built models in the early 70's seemed to retain the brazed on cable stops on the side of the top tube from earlier models before these were removed completely. like yours, in late 70's/80's. Its difficult to pinpoint an exact model, but has all he hallmarks of a good quality frame so could be a contract clone of various Holdsworth models either built by them for someone else or built under licence from them.
Hope this helps, more pictures might help.