Anthony Pratt
As with all of these problems after a lot of head scratching I finally arrived at a conclusion. Looking at the Dapol spares page on line I see that the bogies are held in place with a split pivot post, and two vertical metal contacts, no wires. Sorry to the experts but this is my first time modifying a Dapol product. Two thin metal blades were inserted between the bogie and the underframe and by gently pressing together against the top of the pivot post I was able to remove the bogie.
Now being able to see the wood for the trees so to speak I decided that it would be possible to remove some of the plastic moulding behind the metal bearing/pickup plates to enable the plates the move out to allow the EM gauge pinpoint axles to fit. A fine tapered wedge behind the plates enabled a thin file to fit in and remove a suitable amount of plastic from the inside of the bogie frame. As is with all of these jobs care time and patience are required.
I am pleased with the result with a free running coach with all of the DCC functions operating.
Sorry for the ramble but it may help someone else to convert the Auto Coach more easily.
Anthony