Certainly when I started going to Exeter st David’s on my own in 1986 there were mk3 sets going to Paignton on summer Saturdays behind pairs of 31/4s and occasionally the odd Peak that had slipped through the Iron Curtain (Bristol TM).
We even had the named Pullman mk3s coming through and as I started bashing I had plenty of runs in them including when they started coming down with the DVT still attached. Great times I must say.
Use of the Pullman sets was a regular booked thing, certainly in 1986. For the summer you had the following set utilisation on Saturdays:
WB300 Mk2d BSO, 3 Mk3a TSO, Mk3a RFB, 3 Mk3b FO, RKB, Mk3b FO
1V47 2326 FO Manchester Piccadilly-Paignton
1M37 0820 SO Paignton-Manchester Piccadilly
WB302 Mk2d BSO, 3 Mk3a TSO, Mk3a RFB, 3 Mk3b FO, RKB, Mk3b FO
5V36 0635 SO Euston DCS-Milton Keynes
1V36 0715 SO Milton Keynes-Penzance
1M82 1540 SO Penzance-Milton Keynes
5M82 2234 SO Milton Keynes-Euston DCS
MA300 Mk2d BSO, 3 Mk3a TSO, Mk3a RFB, 3 Mk3b FO, RKB, Mk3b FO
5F49 0700 SO Longsight CS-Liverpool LS
1V49 0840 SO Liverpool LS-Paignton
1M65 1625 SO Paignton-Liverpool LS
5H47 2230 SO Liverpool LS-Longsight CS