As I have said the signal I chose was the one from Cambrian Models. This was done purely on looks. Model Signal Engineers, Garden Railway Specialists, and Tolhurst Model Engineers all supply signal kits in the 16mm scale -feel free to choose...

 This shows the Cambrian Models Kit for their signal. The instructions are quite complete and they tell you what you need to complete the kit. Note the pre-finished pole and length of 1mm brass wire -everything else is in the kit.  The post was made from a length of 15mm square Meranti planed down to 12mm square and the top tapered with the aid of the side of a grindstone. All the signal posts have been tannilised and coated with exterior varnish before painting .

The finial has been assembled. The two bosses that support the signal shaft have been CA'ed to the post. The bottom counterweight bearing has been fitted to the bottom of the post. The shaft for the signal arm has been epoxied to the arm and the platform support epoxied into a slot in the post.

The finial has been epoxied to the top of the post. The counterweight fitted to the bottom of the post and the 'back blind' for the signal fitted to the signal shaft. NOTE: getting it in 'just the right position' is NOT easy!!!  

I assembled the counterweight on the other side from the drawing in the instructions -this is because in my case it will make installation easier. (There is also an M5 nut stuck to the counter weight to help 'take up the slack' on the operating cable!!!)

The filters for the signal have been trimmed and stuck into their places on the arm -as this is a 'lower quadrant' signal RED is at the top and BLUE beneath it. The length of brass rod is suitably bent -the active length is 22.5cm in this case. The cramp is holding together the light box as it sets.

This is a close up of the 'back blind' and lamp box assembly. Although it is difficult to see properly in this shot, (the one above is better), the 'back blind' has a U shaped notch in it which lines up with the hole at the back of the lamp box. So, when the signal is at 'Danger' there is a small amount of light showing from the back of the signal informing the signalman that the signal is at 'Danger' -this is obscured when the signal is at 'Clear'.

Here is a partially completed 'Ellis and O'Donnel' signal from the Cambrian Models kit -only the wood post has been painted thus far...