Thanks for all the help guys, I will do the tests now.
I thought the test I have already performed was sufficient to rule out the transistor: Using an almost dead pp3 to power the motor stopped the relay holding ON at all.
The relay is definately a 6V, but the click is nowhere near as audible as other identical relays I have on other boards.
I like the idea of using optocouplers, but they seem to be such tiny devices.
Can they handle alot of power?
Does anyone have any links to websites which cover optocouplers.
Eventually I want to be able to switch 2A at 9V with a 6V signal.
Ill post back once I have done the tests.
Cheers
John