thanks for that Obrian I found these pics years ago after my dad passed away and always assumed it was a BSA
because the bikes he had when I was a kid were all BSA's, his twin brother had Norton's maybe it was one of his, they where identical twins but I know this is my Dad cos of the woodbine in his mouth on the first pic and his twin never smoked. if anyone could tell year of the bike would be nice to know also