Although the DTMF version of the Direct Line promotional telephone has a case based fairly closely on that of a red
GPO 782 (apart from the addition of "wheels"), the internals are entirely electronic and bear no resemblance to those of the 782. I assume the same would be true of any ten-button loop-disconnect versions that may have been produced.
If anyone actually has one of the ten-button versions, I'd love to see images of it.
Meanwhile, here is one of my twelve-button (DTMF/LD switchable) ones: