Thanks peterm. All clear now. I'd double-counted 27d as type 1 and 2 and not counted 27a (type 3) at all so thought I was a type 3 short rather than a type 2.
If you see what I mean!
All done and seem to connect but the clue area on my page is such a mess of scored out bits, joining arrows, type 2-4 numbers and added/subtracted letters that I can't face trying to marry everything up so I'll just assume it's perfect!