Emmeline, it will depend on whether your shower unit is already fully enclosed. If it is then, including the installation of steam and purchase of steam generator, you would be looking at around £3500. If it isn't then one would have to pay for the shower unit to be enclosed properly as well.

You should factor in the cost of replacing the curtain frequently. A screen would cost about £50 on Amazon, and a curtain much less. But, you'll get mould on the curtain often, and the cost of replacements would soon add up. you might also want to think about visual space. The room will look larger with a glass screen as you can see through it to the back wall. An opaque curtain would create a visual block. Having said all that, there are advantages to a curtain. You could pull it all the way back when bathing children. (Check you see whether you have enough space to open the shower screen all the way. If so, there would be no difference; if not, the curtain would offer more flexibility).

i have a shower bath....my oh loves a bath, me and the kids prefer showers so we"re all catered for. just had a total bathroom refit and I love it so much, its very modern looking, glossy black vanity and bath panel ,glass and chrome tiles, black flooring and loads of mirrors.....

Roller shower blinds have been available for quite a while - we had one years ago at a previous house and it worked really well. Although it was white, it didn't mark at all in the 5 years for which we used it, although we were careful to wipe off any stray blobs of shower gel/shampoo and leave it down for a short while after showering so that it could dry/air off but it did just seem shrug off any water. Weighted rods at the bottom kept the blind hanging straight down and it didn't get sucked towards you like a shower curtain does. The rods were in three pieces - a longer one in the middle and two shorter ones at the ends so that the blind could follow the curve of the tub at the short ends. This arrangement meant that no water escaped the bath tub. It looked neat and unobtrusive when wound back into the cassette. Shower screens take much more looking after, in my experience, so I wouldn't choose to have another one. If I remember, our blind was relatively expensive compared to a shower curtain, but the looks, the ease of use and hardly any maintenance requirements made up for that. Out blind was still in pristine condition when we moved out. The next house had a separate glass shower cubicle - nightmare! Current new-ish home has a good quality, weighted shower curtain but will soon have a new shower blind. IMHO, you wouldn't regret getting one too.