It's even hard to find a pie and mash shop in Walthamstow now.
No doubt there may be Gastro Pie and mash shops catering to the " new " eastender. The EEC has a lot to answer for in destroying memories of childhood, unless your French or German.
I have just moved here from the east end of london and believe me the original pie and mash shop with green liquor and jellied eels is still alive and well. Not a fan myself though!
I believe the sausage roll in question was actually the pork/sausage mince variety rolled in pastry.
If so, I have found the pastry variety in La Rose Noire Bakery in Causeway Bay (in Wellcome on Paterson St). Not the best though, and certainly doesn't rival the kind I used to get from Aussie bakeries.
I've resorted to making my own, as the mince is available from time to time in the International supermarkets.