Thanks for your responses, I think the delaminating may be restricted to only the edges (at least that's what I want to believe), I tried lifting the untrimmed glass around the cockpit in a few places & it's quite firm, the glass actually tore & broke off rather than lift.
I have since cut away the offending sheer edges that were lifting & then scraped down all of the ragged edges & it doesn't seem quite as bad as I first imagined although the edge is very uneven, but at least it will all be covered by the joining tape (perhaps a little wider) & should mostly disappear.
For me, the glass & epoxy work has been an extremely steep learning curve & has been the one process I have had the most trouble with & not enjoyed, nevertheless I will definitely be paying a lot of attention to the joining tape when the time comes; washing, scraping, coarse sanding, whatever it takes.
Glen G.