I have an old rechargeable torch (FWIW:
http://www.comparestoreprices.co.uk/camping-equipment/coleman-charger-1-krypton-spotlight.asp)
which has soldered-in and now clapped-out NiCd batteries: it was very
effective for many years and so I'd quite like to repair it with new
batteries.

I've got it in bits now and exposed the batteries; however they aren't
the same physical size as 'ordinary' ones so I'm struggling to know what
to look for in terms of finding replacements. I'm sure someone here
will recognise them:

There is a pack comprising two cells mounted end-to-end encased in that
rigid white plastic heat-shrink type stuff, with a solder tag at either
end. Has sticky label with "Energizer" and a long serial number,
41B030AC17601 9641, which Google doesn't recognise!. Dimensions of each
cell are about 41 mm long x 20mm diameter. Does this sound familiar?

No clue as to Ah rating. Charger is 240V / 2.5W; 4.8VAC / 120mA

Are they usually bought as a pair already made up as a pack, or will
have to buy 2 cells separately and get the duct tape out?

Thanks for any pointers
David