Sounds about right, unfortunately.
We put a new bathroom in, in 2009, and unlike most people we know, don't have any family or friends who will do stuff at 'cost price,' or for mates rates. So it cost us £4.5K even then. (For a 7 foot X 9 foot bathroom!)
We initially got a quote that was £2.7K, which was OK, but when the guy doing it, started to fit the shower, he said our electrics are outdated, and potentially dangerous, and need changing. THAT put it up by £500.
Then the tiling bumped it up by about another £700, (for the labour for him to do it.) Wasn't included on the original quote, and they claimed it was just for the price of the tiles, (on the quote,) and it didn't include labour. 
Along with several other things, that conveniently had not been included, it ended up being double what we had first been told. The work was already well underway, so we couldn't back out.
Also, we got rid of our old steel bathtub, and had a new plastic one. Worst decision ever - it was fucking awful. Within WEEKS, the steel bars that were supporting it, started to cause a dark shadow at the bottom of the white plastic bath. Shit it was! We will never, ever have a plastic bath again. (We are in a different house now, with a STEEL bath!)