Aspen Glass?
Carl,
I would think that an Aspen PFD/MFD could be fitted along with a Garmin GTN 6xx/7xx series NAV / COM box which should be quite straight forward to get STC'd for UK.
A really good port of call would be Jimmy at Sharman Avionics based at Sywell. Really knowledgeable and will walk you through the steps required for certification.
I have had some dealings there, if you want more info, feel free to PM me.
FF