We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "The Medway Handyman"
saying something like:

Just got a flyer from www.itslondon.co.uk who have special offers on Makita
batteries amongst other things.

14.4v x 2.6Ah NiMH battery for £30 + VAT. Seems good to me.

I currently have 1.3Ah NiCD's, so I guess the extra Ah would be useful, but
is there an advantage or indeed disadvantage to NiMH batteries? I guess the
same charger would work?

Depends what model your charger is. Couple of years back I bought a
Makita 14.4V charger that happily charges NiMH and NiCd, both properly.
It does say on it, but it's in the van and I cba digging it out this
time of night.