Lily I think any time salesmen come to your home you are in for a hard sell. If no prices are advertised then there will be the inevitable initial super high price, then the call to the ‘manager’ in the ‘office’ who will offer a ‘reduced’ price but you have to agree to it there and then and pay a deposit.
I really prefer a bath but having difficulty now so will read comments with interest, but though not a shower fan think it’s the only alternative so will go somewhere like b and q to choose and get their contractors to fit.