Hi can anyone tell me the right way to release the wiring plug on the Throttle position sensor ( the one with the spring wire clip around it) on a TW Magna.

Mitsu likes putting locking devices on all of its connectors, and all seem to have different ways of unlocking. lol
Locate the locking tab and see if it can be pushed below the level of the wire, or if desperate, lift the wire carefully with a small flat bladed screwdriver while you pull on the plug.

Just lever the wire off. There are no tabs to push at all

I used a small jewller's screwdriver ($2 a set at Dick Smiths) under the wire and if memory serves me correctly, I might have use two. One to hold the wire up on the top then fiddle around with the one underneath. On the bright side, they go back on very easily!