Toilet + sink set = £140 from Wickes
Basic bath & panel = £200
Taps = £30 from Screwfix (x2 for bath and sink)
Flooring = £50 for basic cushioned flooring
Shower screen = £100
Basic tiles @ £10/ sqm = £100
Paint £20
Labour = £120 per day X 2 days
Other costs (plumbing, wastes, sewer pipe, etc) £100
There you go. Bathroom for a grand.
Kitchens can be bought dirt cheap from trade / ex display etc. Our plaster costs £100 per day. Painting is easy to do yourself.
Carpets from a trade supplier can be £5/ sqm + fitting if you want to buy that cheap.
We do lots of renovating and it's much cheaper to buy the bits yourself and get a tradesperson in at a day rate. Or do it all yourself if you're handy.
We've just put a huge two-storey kitchen extension on the back of our house (bifolds, u/ft heating, stone floors, roof lights, bedroom with balcony etc) etc for thirty grand doing all the labour ourselves (apart from a bricky who charges £100/ day and someone to sign off the electrics). It would've cost £120k if we'd employed someone to do it.
It does help to have a tradesperson for a husband.