Replacing a zapper key fob the cheap way

I have just bought an 52 1.8 TDCi focus and the key fob (lock, unlock and boot release) buttons didn't work. I changed the batteries but still nothing.

I went to my local Ford garage and they wanted £51 + VAT for the new fob and then £60 lab our to programme it for the immobiliser. Steep I thought...

The parts guy called the mechanic through to check if it would really be that much and he told me the following.....

Buy the new key fob (£51 + VAT) and do the turn the key in the ignition 4 times to register the buttons as per the handbook. When you open the fob you can see what looks like the IR bulb of the remote sticking out covered in rubber at the top (usually covered by the key part). Now this bulb is the part that deactivates the immobilser. SO take a paper clip and push it under the rubber at the back of the bulb (inside the fob) and carefully lever out the torpeado shaped bulb on the new fob. Then do the same with the old fob and swap the bulbs over. Put the new fob with the old bulb together and push into the key. You should now have a working key and fob saving yourself £60.