Well...the last Indian meal I had was in Dudley, and I think two of us ate ourselves mad and spent less than £20. Between us, not each.
That's for poppadums, starters, main course, veggies and naans. And possibly kulfi.
That was a non-licensed Balti place, so we took our own beer.
Looking at the local takeaway, onion bajii, chicken tikka massala, some veggies and naan / rice / other starchy thing, you'd easy get change from £18. The local restaurants charge much the same, and about £4 a pint for Kingfisher or Cobra.