Thanks guys; much appreciated
@ Billchuck: I've gone ahead and ordered a small batch of the stuff to play with and see if it fits the bill. I can collect it at the parcel center this afternoon, so I'll have a go at it this weekend...
@ Mischka: Go ahead and do it. I must admit it's some of the most satisfying hobby time I've had in a long time! Also; I've watched a lot of great Youtube videos lately of people doing plasticard scratchbuilds, and there are some absolutely bonkers projects out there, believe me...
One of the gobsmacking projects I'm following right now is a guy scratch-building a mech(a) completely from plasticard, -rod and -strip. His accuracy and precision is just insane and certainly something to aspire to. he won't be needing any filler in that project, believe me!
And some of the tools he uses, I'll be getting myself for sure.
But he actually uses the Tamyia glue you mentioned. Also, the artist formerly known as Jimbibbly, aka OSHIROmodels, mentioned in one of his threads on the LAF that he uses a similar glue, so those combined lead me on the search for just such a product.
I might well try to get my hands on the Tamyia Extra Thin Cement at some point too, even if just to compare it to the other glues I've accumulated over time