Cost to tank a kitchen/ remove cement render

[Bumpsadaisie]

any ideas how much we should budget for tanking a kitchen say 5m by 3m? Seller says they have a quote of £3k to tank the kitchen which seemed low to me. Obviously you would need a new kitchen too but leaving that aside, how much for the tanking?

Also, this is a very old cottage with 0.75m thick walls. In the 70s it was covered with cement render.

Inside it now is a bit damp and musty. Would want to remove cement render and take it back to stone (possible repoint), so that the house can breathe and dry as it was designed to do. Any idea how much? Its a 3 bed detached cottage with 2 floors, not tiny but not huge.

Any tips enormously appreciated xx