By the mid-50s the class were becoming more widespread. According to my Spring 1957 Locoshed book, 69612, 69615 /8/29 were allocated to 34B (Hornsey); 69616/7/9/20/51/90/92 were allocated to 31A (Cambridge); 69621/79 were allocated to 32C (Lowestoft); 69631/2/5/7/8/9/44/8/9/50/4//704/9 were allocated to 34C (Hatfield); 69672/5 were allocated to 30F (Parkeston); 69673/8/21/7/32/33 were allocated to 30E (Colchester (sub sheds at Braintree, Clacton, Maldon and Wlton on the Naze); 69694/5/8 were allocated to 33B (Tilbury); 69696/708 were allocated to 32D (Yarmouth South Town); 69706/7 were allocated to 32A (Norwich) with the remainder allocated to Stratford (30A) or Hertford East (30B)
A quick trawl of some books has turned up quite a bit of photographic evidence for N7s away from their usual London haunts.
There is a nice (but undated) photograph of 69707 heading the 3.15pm milk train from North Elmham to Ilford near North Elmham (exact location not recorded) on page 60 of The Great Eastern since 1900 by Charles Phillips (ISBN 0 7110 1402 7)
69707 appears in another undated print on page 59 of Doctor on the Line(ISBN 1 871608 24 4) heading a 12 coach train from Newcastle to Yarmouth somewhere east of Norwich (which looks like Acle although the caption states that it was routed via Berney Arms but see notes re plate 126 below). The caption notes that it was one of about 6 to have worked from Norwich shed.
69620 is recorded at Long Melford on page 83 of the same book
69651 is illustrated working the Haverhill to Audley End push pull near Saffron Walden in Plate 49 of 55 years of East Anglian Steam (ISBN 086093 182); 69731 is illustrated near Mistley on a Harwich to Colchester working in Plate 57. Plate 125 shows 69708 working a train from Yarmouth to Norwich and shows the recess in the cab side for the M&GN Whitaker staff pick up apparatus whilst plate 126 shows 69707 at Acle with a Yarmouth bound service. Plate 132 show 69679 leaving Cromer Junction with through coaches from Liverpool St to Sheringham; Plate 153 shows 69689 approaching Coke Ovens Junction with the push pull service from Yarmouth South Town, Plate 12 shows 69679 approaching Beccles on the Yarmouth South Town to Beccles push pull service.
Edited to correct typos!