Well after waiting so long with an open diff .. we saw an opportunity on ebay and went for it ..

Basically our choices were fairly limited with regards to what LSD to get .. the 2 choices were:

1. Get another more modern diff and fit everything onto this new diff

2. Find an old Escort LSD. This option is very rare and also very expensive. A stock LSD for the Ford Escort is not only very rare .. but if you can find one it nhas collectors mvalue (almost) and so is expensive .. and its probably burnt out anyway!!

Anyway along the same lines, a Quaife diff for the Ford Escort is almost 450 pounds sterling, here what the web had to say about it ..

Quaife ATB diff Ford English 16T spline. [QDF5Z/16] £448.62  Quaife ATB diff Ford English using 16T spline half shafts. Quaife Part No. QDF5Z-16 Quaife ATB differential for Ford English 16T is suitable for Mk 1 and Mk 2 Ford Escort using 16 teeth spline halfshafts. A direct replacement for the standard Ford Escort open differential, the Quaife ATB differential transforms your car%u2019s performance. Unlike a conventional plate-style limited slip differential, the Ford English 16T Quaife ATB differential relies on gears rather than clutch plates for its operation. That means it is much smoother in operation. The Ford English 16T Quaife ATB differential never locks harshly with a set pre-load of wheel slip across the driven axle, like a conventional LSD. Rather, the Ford English 16T Quaife ATB differential automatically biases the torque away from the spinning wheel across the axle, to a constantly varying degree, and never locks. The Ford English 16T Quaife ATB differential has many benefits over a standard open differential, including maximising traction and minimizing wheelspin, eliminating torque steer and snatching in front wheel drive cars compared to conventional LSD units, and a maintenance-free design which retains the standard oil lubrication. The Ford English 16T Quaife ATB differential is proven in circuit and drag racing, rallying and road use, and is produced from Corus steel billets, and is CAD designed and CNC machined, then inspected to ISO 9001 standards. With over 170 applications, the Quaife ATB differential is second to none. Accept no imitations! Quaife ATB differentials are used by Ford, General Motors and Daimler-Chrysler as original equipment.

 The other alternative was the tran X diff .. heres what the web had to say about THAT:

Ford English axle plate type LSD [LSDFEA] £548.7  4 plate (heavy dyty adjusable) limited slip differential for English axle with English splined side gears. Larger journal diameters than the Salisbury type diff, and comes complete with journal bearings included in price. Eight variations on settings.Ramp Angles 45/45 55/90 45/90 35/90 Preload 25/30 65/70

well .. we disregarded all the advice and bought what we thought was a Jack Knight diff .. because of this email from the seller .. Jack Knight make a diff for 700 pounds thats a proven awesome racing diff .. we thought this may have been what we were getting ..

Dear posh868,

Hi,
No its not Quaife. I believe that these units were made by Jack Knight, but I can't find any identifying marks on it. Not sure what you mean by 16 teeth - there is no crownwheel on the unit, it takes the standard English crownwheel and pinion, but as with any diff its very important that its set up correctly so that you don't get rapid gear wear. It will fit inside a normal English diff casing. Hope this helps.
Cheers
Rob- 68robral

It turned out to be a Detroit Locker .. which is very different!! .. heres what they have to say about this type of diff .. its not even an LSD .. really .. its more used for off road or drag racing .. I suppose it will be great in the dirt!! and possibly great for drifting!! great!! .. heres some pics of the stripped down toy and the write up

When it comes to providing traction, only Eaton offers a solution for every traction need. As the world's largest producer of differentials, Eaton provides innovative traction solutions to OEM’s and the automotive aftermarket.

Eaton limited slip differentials like the Posi and Detroit Locker dominate the performance market as the choice of professional racers in NASCAR, NHRA, IHRA, CORR, NMRA, NMCA and other racing associations. Off-road enthusiasts, rock crawlers, trail riders and ATV buffs also crave the superior traction that the complete line of performance differentials provides.A heavy-duty product line of “apex” differentials built exclusively for military vehicles, construction equipment, heavy hauling, forestry and agricultural vehicles attests to the inherent strength and high quality of Eaton's entire line of premium differentials.

Beyond the rigors of every day competition, all products are proven and validated at Eaton's Proving Grounds in Marshall, Michigan, where it has complete testing facilities and on-road/off-road test tracks.Locker or limited slip? Clutch or gear style? Automatic or electronic? Only Eaton offers them all.

So were going to install it this month and I'll report back on the workings of, noise of and effectiveness of this locker diff ..