Series 3 rear diff fill plug - Where?

I am slowly working through changing all the oils and greasing all the nipples. I am at the back last job is to replace the rear diff oil. I cant see the refill plug, what am I missing? Its looks like a standard rover diff and according to Haynes it should be on the drivers side fron of the diff casting in one of the casting veins. I cant see it although light was poor. Is there some diff without refill plugs and if so how do I refill?

my refil plug was on the rear but I've got a sals axle

its either in rear pan or has had diff swapped ,could be filled through stub axle with drive member of and jacked up that side

Not on rear pan, not a sals axle either

its had diff swapped then,they where filled through hole in diff housing as you described but later through rear case,you have later diff in earlier case

Must have been swapped as I have range rover diffs. Have taken half shaft out and done it. Thats all oils changed and all nipples greased. Come on winter!!