Hoo Hing has another branch near Mitcham and one somewhere in East London. There's Wing Yip as well as See Woo which have branches thru out London, but not down here. Paul's probably best bet, get a box of 1lb squid from frozen seafood suppliers (prawnman). If the angling shop runs out of squid by any chance, go to Wah Hing in Boscombe or Didcot Ind Est, they have both 1 and 5 lb block for sale. In Southampton try Yau's brothers near St Mary.