Funny you should mention the RAF Fire Axe KnC - my first airframe repair job in the early 70's was to the Wing L/E of a Canberra at Cottesmore,It was a smallish 'Square' hole which exactly matched the standard Fire Axe 'Spike'.
We could not get any leading edge section (or so I was told) so I had to 'roll' it myself in station workshops,the workshop techs were less than helpful because they had lost out on the 'pay bands' not long before.
We borrowed some hangar space for me to carry out the repair,just before I had it sprayed,the Hangar Sqn Ldr Engo came for a shufti and said ''I have seen better workmanship on my pushbike'' - but he was a miserable old ex brat with no SOH.It actually looked ok when covered with 12 gauge paint
I do not think the culprit was ever found
