You might consider using a self cancelling module for the signals. I mounted signals on my Vincent and used a self cancelling module that is also the flasher unit. It is about half the size of a candy bar.
I used the self canceller on the Vincent because I noticed that I am often leaving the turn signals on when riding my 75 Commando. This is very dangerous, especially if you happen to unwittingly have the left hand turn signal on when going thru an intersection where an opposing car is in the left hand turn slot(same kind of situation would be right hand turn in UK). He sees your left hand indicator and makes his left hand turn, cutting you off. I've come pretty close to killing myself this way and only realized it was my own fault later when I finally found found the signal left on.
The self canceller I have uses right and left momentary switches (I used Honda dirt bike kill buttons, $9.00 ea) Hold the button on for one second and you get seven flashes, good for changing lanes. Hold the button down for two seconds and you get 18 flashes, good for turning a corner on a green light, hold the button down for 3 seconds and you get about 60 flashes, good for sitting at a red light waiting to make a turn. Hold both buttons down at the same time and you get four way flashers( called hazard lights in the UK?), press them both again and the four way flashers turn off.
I purchased the module at Signal Dynamics Corporation. I've forgotten the exact price but it was under $100, I think it was $69.