I'm all done - more luck than judgement - and getting several entries by the 'only possible fit' method, before reverse-engineering the parsing - or actually not fully getting it in some cases.
I've been following the conversation between HW7 and Midgers with some puzzlement - I can't see what Midgers means by 'a prefix' for one of the thematic entries- and why only two 'chimaeras' - I have 6 'chimaeras' as stipulated in the second sentence of the preamble - 2 do double duty - and they're all 'real' words given the 'Chimaera' convention, and serve the theme precisely. Allowing for this convention, I have no non-words. (I hope this isn't giving too much away,
pace Quisling... )
IHaving jumped in triumphantly with a ridiculously obvious solve and entry in the first ten seconds, I was horribly frustrated when nothing would work with it - then the penny dropped about the 5 'needing changes' and all was sortable - although one altered entry isn't actually in Chambers - but 'in thematic locations'? And 'all in the top half because of the theme'? I really can't see why the 5 changed entries - which are asymmetrically distributed in contrast to the rest of the thematic material - have to be where they are, or what they represent.
I'm not expecting any hints or nudges about this so early in the week, but I'd like to know eventually - even though I'm pretty confident I've got a submittable grid.