Keep your eyes open on the GWR between Exeter and Penzance. The GWR are doing trials on a mini-hst (2 + 4). The carriages are not the usual HST stock but MK3 coaches with the doors altered to sliding doors. At the moment it is running in GWR green livery with one engine being Old Oak Common. A.t the moment it is stuck at Longrock for repairs to one of the carriage doors. This means you can run a 4 car HST on your layout. If I can grab a pic of it I'll post it up. Video of it here
A similar initiative is about to enter service in Scotland, commencing May I believe. A mix of 2+4 and 2+5 sets. A 2+4 has been testing/driver training on the ECML past my village for the last 6 months or so. https://www.flickr.com/photos/emdjt42/39999583414
