Hello Chris,
Oh dear, that's a first, sorry
From the original B.O.M the capacitor details are (Farnell sourced) -
9708340 CAPACITOR, 10UF, 16V MULTICOMP - CB1C106M2BCB
It may be worthwhile replacing the 1N4001 polarity protection diode too, if it has suffered potential stress like that.
If you need a new casing, I still have some and can send you one FOC. I
should also still have all the bits to make up a new input power connector assembly, should you need one of those. Just let me know.
I've always used a better quality ("Mascot" brand from RS) 9V regulated "wall wart" supply, and that is what I used to supply with the unit for people who also wanted the PSU included.
Let me know if there is anything else I can help you with.
Graham.