Also, the strap has come off on one side, and the pin seems to be broken, plus the winder feels a little bit too precariously attached...
You can buy spare strap bars on eBay for next to nothing. Just get the right size by measuring the gap.
The winder is held in place by a small screw underneath the case back. This needs to be adjusted correctly, so most likely it'll just need to be tightened slightly.
I've not used any London repairers, but you shouldn't be paying much at all to have this done. I'd consider having a fresh gasket / seal fitted on the case back to aid waterproofing.
You can buy spare strap bars on eBay for next to nothing. Just get the right size by measuring the gap.
The winder is held in place by a small screw underneath the case back. This needs to be adjusted correctly, so most likely it'll just need to be tightened slightly.
I've not used any London repairers, but you shouldn't be paying much at all to have this done. I'd consider having a fresh gasket / seal fitted on the case back to aid waterproofing.