After a couple of weeks of trying to find some suitable rear shock absorbers I finally came across a local mechanic who did a search of his stock and found a pair of KYB 443020 shocks that have the required length and stroke. ( 11 inches compressed and 17 inches extended, centre to centre ) The only difference is that these have bushes with a metal tube each end. They need 1/2 inch bolts to secure. So out can the top pins and in went the bolts. Needed 3 1/2inch long at the top and 3 inch at the bottom. Only needed a few minutes to install.
For info KYB 443020 shocks are listed for the rear of a Mk 1 Ford Escort (1968-80). Hope this helps.