Ok here's a few photo from an old layout. There is no garentee I will find one of the turntables as I would have to unpack six crates of layout kit to find them following a house move. Your turntable is powered in two ways from the cabin there are two brown wires and these are for the motor which rotates the table, these have nothing to do with track power for test connect them to the output of you H&M increasing the voltage increases the speed and that ugly noise.
The hornby turntable in it simplest form is designed to collect current from the track relay it to the turntable bridge and the out going track is powered by the same means. With a few simple modifications you can make it more acceptable here are some photo's to show you how:
sinking the turntable into the baseboard is a good idea and you loose those ramps which makes operation easier
there was a Peco turntable in this position before. I could'nt find a Flieshmann turntable at the time so I used a Hornby
as a test to see if I could improve it.
I removed the unwanted road with a scroll saw this also improves the appearance
the contacts to relay power from the bus to the ingoing track are arrowed the other contacts are not needed.
here you can see the contacts used for powering the turntable
it might not be clear but you should get the idea
the finished result.
As I said if I can find a turntable I'll post some more photo's for you tomorrow.