Hi Ferdy,
I can't give you a full answer but hopefully this will give you some pointers. I've not finished my Tamar yet, hence no pics.
I'm using 3mm high bright LEDs wired in parallel to run on 4.8v with a 220 ohm resistor. I don't have part numbers but Maplins or Technobots sell them.
My plan is to use a servo and flex link to raise and lower the mast. I'm going to remake the white metal cast mast base using brass U section channel. One of the guys on here had the servo horn exposed with the servo mounted behind the back panel on the wheelhouse and used a rigid link to actuate his mast on his Speedline Tamar.
I've got a Graupner geared radar motor but I've heard Graupner may not be making boat stuff anymore(?). It won't fit inside the vac form kit housing so I'll be scratch building that and possibly also scratch building the radar arm too. The wiring looms for the mast on the full size boat are inside flexible conduits attached on the outside of the mast so I'll be copying that for my boat, as I did on my MS Trent, it saves trying to hide the wiring within the mast!
Hope that helps a little.
Phil