I would like to confirm that is a hardware problem, and no software can solve the issue (other than applications such as "Signal Boost" by Orange, which uses a WiFi connection; but does not increase GSM reception).
I have followed the photos above, unfortunately I do not have a soldiering gun, therefore tried various different methods. I applied copper cables, and that seemed to work. But it wasn't too effective and came loose too often; so I put some staples in (I have not stapled anything). I have taken out a staple, bend it, and made the two items touch. I have placed 3 staples to increase connectivity, and I now recieve full signal [on O2/giffgaff] indoors.
I wouldn't recommend the staple idea, since it can come loose if the phone is dropped. What I would recommend is that you solder, or ask for a warranty (if you're out of warrenty, you can blag it to the CS).