For the high summer period this summer, 6th July until the 31st August on Fridays only FGW▸ will again be running a relief service from London to Exeter. The outward run 1C00, the 1436 London Paddington to Exeter St Davids is booked to run via Swindon and Melksham. Should pass Melksham around 1600, the first booked call after Reading at 1508 is Westbury at 1614. It's a chance to travel on some fairly unusual track for HSTs▸ . The return run 1A30, the 1820 Exeter St Davids to London Paddington runs non-stop from Taunton to Reading via Bristol Temple Meads. It departs Taunton at 1848, is booked through Bristol Temple Meads at 1920, booked through one of the through roads at the station rather than a platform, rather rare in passenger service and arrives Reading at 2020 and London Paddington at 2052.
Absolutely BRILLIANT! Thanks for this info. I've been waiting ages for a service like this. I live in Bristol, but will be travelling down to Taunton or Exeter on a Friday evening in July or August especially so I can travel on this 1820 Exeter St. Davids-London Paddington service. Non stop through Bristol Temple Meads, Bath Spa, Chippenham and Swindon - very rare nowadays!
EDIT: Just realised you didn't state which route the service would take from Temple Meads. If it's booked to pass through Temple Meads at 1920 it's more likely to be running via Bristol Parkway, as a service to Portsmouth Harbour is scheduled to depart at 1922. Whatever though, still a very interesting and rare service this will be. I'll book my tickets for this one!