Hi Gerry, is it a MkI or a MkII? If a MkI the end is like a big cast square block with a switch you slide forward to release the cocking lever. If a MkII, it will have a push-in button on the end of the cocking lever which locates neatly on to a pin in much the same way as on the HW77, HW97, BSA Superstar, and BSA Goldstar .
I have owned one of both types. For me the MkII is the superior of the two as (a) doesn't look like it has a matt black tobacco tin welded to the end of the barrel, and (b) the MkII has a small unscrewable circular thread 'keep' on the end of the barrel which once removed will let you fit a silencer .
Both mine were .177, and again the MkII gets the vote here as was/is much less jumpy than my MkI. Both are highly collectable these days tho, but do be careful if mounting a scope as the chamber on the Eclipse is made of alloy (not the usual steel) to keep the rifle's weight down, and so will crimp and buckle if you over tighten your mounts .
I wouldn't be without an Eclipse in my collection now however, be it MkI or MkII. Both are rare as hens teeth (especially in .177), and both pay a tribute to the once great Birmingham-made name of Webley & Scott (R.I.P). Am a bit of a British Brum made anorak to be honest (see signature), so any questions, feel free to p-m me .
ATB: Gareth W-B.
ps (added as of edit date below): forgot to say that this is a lift of my original answer to Gerry's original thread in the general section.