You might find drips and drabs scattered about Squeeth but I think you'll be lucky to find much. Sommecourt (amongst others I'm sure) might have some pointers as he's more familiar with the PRO/NA and has turned up some very nice after action reports in the past.
N&MP sell facsimiles of stuff along those lines but they're few and far between and always quite pricey. There's one on the Administrative History of 21st army Group from 1946 I've wanted to look at for a while but it's proving hard to find, and as I only want to check one passage it's not worth the thirty odd quid to buy.
I'm building up to a first PRO visit, seems it just has to be done eventually
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Cheers,
Adam.