Step 3: No Going Back Now!!
For the new antenna, I used a 30mm (CRITICAL!!!) piece of rigid copper wire (earth wire etc), which gives a better bandwidth, but is also liable to pull the old antenna track away from the PCB if soldered directly onto the track.
For this reason, I made a small hole in the PCB, using a small watchmakers' screwdriver (you can use a dremmel or 1mm drill bit).
Whatever method you use, make sure you support the PCB on a firm surface, to avoid stressing the board while you're making the hole.
The antenna is then threaded through the PCB from the other side.
Now it gets tricky, because you cannot hold the wire while you're soldering it to the track (it's too hot), so you need to find a way to support the board while you're soldering it.
Also remember to 'tin' the wire, before you solder it (it gives a better connection, and also solders quicker so you don't overheat the other components).