18th May diagrams, from RailUKforums:
https://www.railforums.co.uk/threads/remaining-gwr-hst-diagrams.164465/page-441A76 0657 Plymouth to Paddington
1B25 1045 Paddington to Swansea
1L71 1429 Swansea to Paddington
1C26 1830 Paddington (pl4) to Taunton
1Z43 2132 Taunton to Exeter St Davids
1A10 0729 Exeter to Paddington
1W29 1121 Paddington to Great Malvern
1P61 1435 Great Malvern to Paddington
1G60 1815 Paddington (pl2) to Cheltenham Spa
1B03 0645 Bristol Temple Meads to Swansea
1L48 0929 Swansea to Paddington
1C16 1330 Paddington to Bristol Temple Meads
1A24 1600 Bristol Temple Meads to Paddington
1W08 1822 Paddington (pl3) to Hereford
1A78 0650 Penzance to Paddington
1C15 1300 Paddington to Bristol Temple Meads
1A23 1530 Bristol Temple to Meads to Paddington
1C92 1803 Paddington (pl1) to Plymouth