Thanks for your replies guys. Really helped ease my mind.
I removed the fuse and shorted the connection to get temporary operation. I did think about replacing it with a fused cable you can get.
But the thought of the root cause returning gave me too many paranoid thoughts. :roll:
So...
The boiler stopped working earlier today. It is a direct fed system.
I've followed the fault finding flowchart in the manual.
Seemed to suggest the fuse or PCB.
I removed the PCB to find that the solder joint had melted where one side of the fuse housing was attached to the board. I...