Anyone able to point me in the right direction on this one ? :-/

You could find a used scissor jack for cars, and an old drill motor that you could adapt to the jack. Also, you could use the "clapper" for a sound operation.

The real issue here is mechanical, not electrical.

You don't need a servo motor. Your first problem is to decide how you want to convert rotary motion (the motor spinning) to linear (the platform moving up or down). Your next is to ensure that the platform will not bind in either direction.

Easiest might be to modify a garage door opener. It produces linear motion, has up and down limit switches (to automatically stop at the top and bottom) and electronics to automatically reverse direction on subsequent operations - and it can handle the weight. You may have to move the limit switches out of the door opener motor assembly and mount them on the frame that the platform "rides" in. You'll need solve the mechanical problem of the platform moving without binds, and figure out how to connect the door opener traveler to the platform and still get the overall "look" you are after.

My first inclination would be to look at a hydraulic jack and motor-driven pump. I think the bits should be available at retail hardware fairly easily. Regards, John

Thanks all :-) Paul