These (and other parts!) fall off of Standards with some regularity. Most people seem to find the connector either rattling around inside the shell or still attached to the compass wire. Others have had to replace the connector either themselves if they have the soldering skills or having someone do it for them.
As far as I know, this is the connector that people use:
BM05B-GHS-TBT(LF)(SN)(N) JST Sales America Inc. | Connectors, Interconnects | DigiKey
I'm not sure if it will be worth it to ship to you in the UK, but perhaps you can source it locally.
There are folks here who have bought several at a time, so perhaps someone close to you with an extra will also chime in. Good luck!