While that may have happened, all the photos I've seen of the stock transfers show them being hauled by London Transport battery locos. Those had a complicated arrangement of folding buffers and couplers specifically designed to allow them to couple to different types of stock including tube vehicles.Similar situation in London with tube stock from the Northern City line being diesel hauled to depot through Crouch End until the Northern City became part of BR.
I have this rather grainy shot of 33034 hauling a 4EPB plus 4CIG rake at Ashtead in February 1985, but as the loco is leading, 'remote control' wasn't an issue. I imagine it may have run round at Dorking but it's possible it returned in push mode.View attachment 131463
Seems people in high places read these forums , in addition to
wcml T-Bjrds at Rugby Crewe and Carlisle And the strategically placed class 67s on ecml a new T-Bjrd will be introduced from next month at Newark (North Gate) permanently crewed with addition of accompanying N R staff to be quickly deployed where required , traction expected to be something from Carnforth pool.
Dellner fitted ? Or gaping hole / plated over where retractable Dellner once stood I wonder !