Hi i have an immobilizer fault, if I take out the key innards and hold it tight against the removed transponder ring and squeeze it starts. I only have one key so if I decide to swap out keys transponder etc what exactly would I need. Many Thanx.
Sounds like a defective keyfob module. Use a magnifying glass, and see if you can spot any "foreign matter" which may be creating a partial short. It may be worth cleaning it with electrical switch cleaning spray and a nylon brush (test the brush with the spray first!)
That simply confirms what has already been said either the key is faulty or the decoder ring is faulty you can get a key done for less than your quoted £100 but the ring is worth doing first as its cheap even new