See pics. They are labeled.

The part in your pic slides onto the tape reader bottom and then 4 screws are in the 4 threaded holes in the machine pan. The center screw is the one that tightens the plate. This allows the TR to be raised, lowered, slid and tipped to fit the cover. A tricky job.

As to the other issue repeating see wiki site for replacing a keyboard. Check that your kybd is fully installed and the H plate is in place. There is an adjustment too but only after all other things checked. You arent replacing a kybd but lots of info in the procedure.

Be sure the printer is in the 4 rubber mounts properly.

There could be lots of reasons for the Repeat key not working correctly.

Does the machine type one character without repeating. If so, the Repeat key is probably not installed in the kybd properly. If the machine repeats after any character you need to check the distributor area to see if the trip levers are moving freely. See last pics. If binding you need to free up by oiling the trip shaft that is way down in the distributor area. See pics. One is of a parts machine just to show where the shaft is.

Greenkeys will bounce this message but you should get it OK. I was going to call you till I remembered you are in UK.

73,

Wayne

KB1FDW