The USB charging port developed a fault after me cleaning all the fluff out so I purchased the USB/headphone module for £3.25 from a poular auction site. I had a couple of hours free today so hairdryer, torx driver and guitar picks in hand I had a go...
Just getting the speaker covers off proved difficult
However I persevered and eventually removed them. Getting the back off was also a pain, however again perseverance paid off and out it came.
Replacing the USB/headphone module was fairly straight forward. Then I put it all back together (the power button ffs...) and went through testing everything and quickly realised GPS wasn't locking on.
A quick search got me to this thread and then off with the back again. It was fairly obvious what I had done (looks like the guitar pick bent the GPS pin), however in my attempts to bend it back; off it snaps..
A carerfully folded piece of tinfoil in a 'U' shape, pushed into the gap where the pin previously was and then wrapped slightly around the circuit board where there are no components and it all seems to be working. GPS lock is what it was before (about 10-seconds indoor 3D fix) and everything else seems to be OK.
Thank you for the information in this thread.
Might be time for a new phone TBH