Of my 3 Discos, only one had a knackered seat base, and that must have been due to having a fattie owner.
But a mate of mine, also with short legs, finds driving his Disco a long way tiring on the thighs. So I suggested he take the base apart and cut some of the foam away from where he pushes his thighs into it when driving, depressing the clutch etc.
He never did as he got rid of it, but you might want to consider it. Or else, yes, pedal extensions, or even a plank of wood underneath your heels so your foot has a higher pivot point.
But a 29" inside leg must be common for both men and wimmins so I think it might be summat else. (It is only one size down from mine for instance.)