Andy- a few other things i have found. the quill is hollow between the morse taper and the threaded end- after using a deep hole borer for a while, it will fill with dust, stopping the auto ejection of the tail centre and ultimately blocking the hole. Just withdraw the quill and poke around with a screwdriver, then blow it out- you do not need to dismantle anything else to do this.
The pin that helps align the headstock in the case of mine actually mis-aligns it. With the pin in place the head and tail centres are 2mm-3mm out of alignment. The pin might serve a purpose, but alignment isn't it!
On the tailstock and the carriage i found the levers far too short, so i turned longer ones and glued them over the steel bars (which makes them longer and wider), which worked well, but i also reversed the underside of the carriage so that the adjustment is done on the back side, so the handle(no matter how long) dosn't get in the way of your tools. This also encourages you to switch the lathe off before adjustment, which saves you dinging near finished pieces by being smart and doing it with the lathe running.
I hope this is of some use.........................Phil.