Sounds like a repair to me.
All parts are in stock and good to go same/next day.
£100.00 should cover the cost of the parts providing your headlamp failure is only a bulb or ballast.
Garage labour will be circa £100.00 - £150.00
Just drop me a PM if I can help further.
Hardly a disaster.
Have a look here:
Always worth paying a bit more for a known members car which will eliminate all the unnecessary traveling that you mention.
I know that the proposed sale has been withdrawn, however may well be worth a PM.
I would go back and check all the fuses in the other fuse boxes with a multi meter before you start looking elsewhere.
I would also check the specific relays.
There are a few common fuses in there, so pay particular attention to those.
How did you get on with the CPS?
I will take that as a no then.
It is within the fuseable link.
It is the only fuse on its own.
The other fuses within the link are all in a row as per your image.