1989 110 rear disc brakes advice needed

Hi all,
Looking for advice...
I have just bought my second Defender, a 110. The rear axle has been swopped for a Salsbury with discs. I am now having to replacing the discs, pads & caliper pistons & seals.
After ordering discs & pads for a 110 before stripping, I have now found they do not fit ?? With a bit of research it seems the pads are the 90 type with spring plates & split pins to hold them in place (no holes in pads). The discs also appear to be the type on my 90 (narrower over all by 1 to 2cm) when compared to the new 110 discs when laid flat on the bench.
On inspection I also need caliper piston kits both sides. So before wasting more cash (& a kicking off the wifey)
Can any one advise on part numbers I need to order for piston kits, pads & discs, or could I just order new calipers & fit with the new 110 gear I already have ?? However, Just by looking it seems the new discs if fitted to the hubs will not fit correctly on to the stub axle, (too wide for front bearing to sit in place).
Thanks in advance...

obviously not a real 300 tdi salibury disc axle ,90 or disco rear discs are ftc1381 pads sfp500200 retaining kit stc8574,pistons 606696 and seal kit aeu1547 only get genuine sweal kit ,std 110 rear calipers are stc1268 and stc1269 can give you other numbers of 110 parts for wheel stationif required

forgot to mention rear discs for 110 are peculiar to 110 and have different offset to others,front solid discs frc7329 fit the same as ftc3846 so you would have to check what stub axles were fitted hubs and whether cailper bracket was std

I ordered some stainless pistons off eBay, please beware, as the description of them is rubbish, he states that the 1989-1994 (200tdi) Defender 90 piston kits fit, when the 200tdi Defender 90's had rear drums, so he hasn't got a clue, but seeing as I did a rear disc conversion it was no problem and it fitted, but otherwise as JM said