I have tried to make a easy to read list of Escort final ratios and what models they came in. There is a huge amount of contradicting information on the internet so let us know if any of the information is incorrect. The following models are Australian due to being most relevant to us on here, unsure is any overseas models are different.

MK1 Escort
April 1970 - August 1971 Had English Differential
August 1971 - 1975 Had Borg Warner Differential
Automatic Sedan.... 4.125:1
Manual Sedan.........3.89:1
1100 Van...............4.44:1
1300 70-71 Van......4.125:1
1300 71-75 Van......4.11:1
1300GT................. 4.125:1
Twin Cam.............. 3.77:1

MK2 Escort 
All Had English Differential
1975 - June 1976 (Pre ADR27A)
1300 Sedan............3.89:1
1300 Van................4.125:1
1600 Sedan (Ghia)...3.54:1
June 1976 - 1981
1600 Sedan/Van......3.77:1
2000 Sedan/Van......3.54:1

Different Differentials
English/Banjo – Gears are accessed from the front
Atlas/Salisbury – Gears are assessed from the rear
Borg Warner – Australian version of the Atlas/Salisbury
 
Differential Lengths
1232mm (48.5”) MK1/MK2 Escort
1270mm (50”) MK1 Capri
1321mm (52”) MK2/MK3 Capri

Great idea

All Australian Mk2's had English diffs
75 to 6/76 1.3 sedans 3.89
75 to 6/76 1.6 2V ghia sedans 3.54
75 to 6/76 1.3 vans 4.125
6/76 on all 1.6 sedans/vans 3.77
6/77 on all 2.0 sedans/vans 3.54
 

Did the early 1600 engine only come in the Ghias?

Prior to 6/76 all 1600 Mk2 Escorts were "Ghias" and they had 16002V motors (Weber/Extractors).
After 6/76 all 1600 Mk2 Escorts had a low compression 1V abomination of a motor that had a terrible tendency to run on.
This change was brought about by ADR 27A (My memory is not 100% so I hope I got that adr number right).
 

The change was brought about ARD27A, the 1300 engines couldn't meet the new standards so they dropped it from their range and introduced the Pinto into the range. 

When you refer to a engine as 1V or 2V what engines does it relate to? Is it just a Ford term? What's the difference between the two? 1V 1600 was a standard low compression engine where as the 2V 1600 was a high compression engine with a weber and extractors. Was that the standard difference between a 1V and 2V across the range of Escort engines?

1v = single barrel carby
2v= 2 barrel crabby
It's sort of old school ford speak, especially old school v8 era. It really only differentiated theinduction side of things but engines could also have other differences comp ratio, heads, cam profiles etc.
1.6 escort
2v had 2barrel weber, higher comp and slightly better cam profile over the adr27a strangled version.

Cheers

So for example with the MK1 Escort 1300 engines the 1300L/XL had a 1V and the 1300GT had a 2V?

Yes.

Cheers