Hi there, it looks like a lovely unit, but I would be reluctant to attempt to rework it. There is rather more to it than perhaps first meets the eye - it looks as though the side panels are, in fact, five separate piece, at least 3 of which (top and bottom frame pieces and centre panel) would need modified, and it would involve rather more than just sawing a small section out!. So you have to multiply that twice, then modify the base, top and any internal shelves. Then you would have to possibly refinish (varnish/oil or whatever) and tidy any newly reworked edges. Oh, and I can't quite see if the top is wood or stone - if the latter, then that has another set of challenges! The reality is that you would need a really high quality carpenter to do a job like this well, and s/he would need a decent amount of time to do it properly. So if you look at the typical daily rate for someone like that - near me, that could be £200-£250 - and factor in at least 1 day, then I am not sure it is something I could justify. If you love the style (and it is a beautiful piece!), why not have a look at Stonearth who do some similar products in beautiful solid woods who might have something in better dimensions? Then you might be able to return or sell on the unit. Or if you really love it, well - 4 inches isn't really that much, is it??

how about continue boxing all the way to the window and use it to house concealed shower pipes and taps also. adding a niche for shampoo and soaps / candles. to have a mirror cabinets above the sink and toilet and under sink cabinet. also fill the gap on the other side of the bath adding a cabinet for laundry / cleaning stuff.

I can’t see any images but it might be my internet connection as I’m in the middle of the North Sea on route to Norway. At home my vanity unit was bespoke made with a drawer pack each side and 2 full height doors under the basin in the middle. Worktop was sourced by us and then loo was purchased separately. Ask a local carpenter to do it. Easy job.

It depends on cost, how long you are going to be in your house, cleaning, and preferences. White is always the least contentious and easy to sell on in future. I do like the wood effect though, I cannot see many people disapproving of that. Its a really good contrast to your floor tiles. If you have hard water and no water softener I would rethink that black tap.