Yes; I think both Mk 1 and Mk 2, and with a question mark over Mark 3. And very nice they looked.
However my purely personal view is that the primary reason for anyone preferring GRP is the reduction in the burden of maintenance, and that from that standpoint the concept was arguably unsuccessful; the main burden of maintenance with a wooden boat is surely the varnish work. For whatever reason the production of composite boats was comparatively short lived.
There is an excellent history of the GP14 hull published (for at least the second time) in 50 Years On The Wter; there is a scanned copy on this site.
This reply was modified 5 months ago by Oliver Shaw. Reason: Typo
If you want a new composite boat Steve Parker turns out some very beautiful boats – I was there this week and they were fitting out a new composite in the workshop – not the cheapest but a good compromise between all wood and all GRP.