Hi Jamie. I used tamarind concentrate in original version of the North Indian Special simply because i couldn't get hold of anything else other than the compressed block. This was in a small plastic container. I would say the concentrate will work ok but not 100% sure on the degree of impact it will have on the overall flavour but i suspect it will only be marginal. I've never seen Tamarina in Tesco or Morrisons and i rarely venture to Asda. I am more than happy with the East End Tamarind sauce i got though ;D Jb, where did you get your Tamarina from?