Rear axle differential ratios.

Here's hoping someone can answer my query about 90 and 110 rear axle ratios ; I just bought an agricultural vehicles which has Landrover axles fitted. However, the diff ratios are special ; instead of the standard ratio (I think) of 3.54:1, mine has 4.7:1, which is a bit of a bugger as one of the axles must have broken in the past and not been replaced with the special ratio but with a standard breakers item with 3.54:1 . Of course I could go to the OEM and get a new diff, but spending that much money to repair an old machine would break my heart.
My question is simple really; I can't believe the maker of my vehicle went to all the trouble of commisioning a special diff from Landrover, for a production run of only a few hundred machines, so did Landrover produce a 90 or 110 (or any vehicle) with this special ratio ? - my machine was made in 1993, if that's any guide.
Thanks in advance for any help.

3.54 diffs were fitted to all coil sprung landies, ie 90, 110, disco and range rover. The 4.7:1 diff is from an earlier leaf sprung series vehicle. The diffs are interchangeable in rover axles. Plenty of both types available from breakers or ebay.

Many thanks you lovely, lovely man; this is what I thought must be the case, so I can now save a bit of money thanks to you!