I have just purchased a 1968 LHD series 1 1/2 4.2 coupe from the US and which is currently about to be shipped to Australia.

I have posted pictures of the back of the seats which is not leather. This trim material looks a velvet-like 'moquette' or fabric.

The side of the transmission tunnel is covered with a similiar material.

The black arm rest is not the right colour!

Question: Is the back of my seat covering and tunnel material "original" trim; do any other members have their seats/tunnel fitted with the same material?

 

Your seat back covering looks identical to what I have on the back of my original 1966 Series 1 OTS seats - it is indeed moquette. The tunnel covering also looks original, but I don't think that is moquette - it has a rather thicker carpet-like pile, though it does look quite similar to the seat back. Your tan leather and vinyl interior trim also looks identical to mine (except for that arm rest). Since that tan shade is a bit tough to find, it looks like your car pretty much has an all-original interior (except for that you-know-what).