I’d paint the walls white, replace the bath panel with a simple white one (there are panels with magnetic doors that you can store items behind but I’m not a fan), I’d remove most of the items from the window ledge, keeping only the essentials and place a plant or two there or a candle. I’d replace the shower curtain with a shower screen if this is within the budget. I would remove all three storage towers and replace with a basket for only a few toilet rolls in the corner. As far as the space at the end of the bath is concerned I see you have the cat tray and litter bag, if this could go elsewhere I wouldn’t box this space in, instead choose a storage unit which fits the space perfectly. Finally new towels which coordinate with your coloured tiles (are they lilac?) will lift the space.

Do you have an alternative spot for the cats loo? If not a shelf over the top would give them privacy and make it less visible. I'm about to put slatted oak panelling on the wall behind the vanity which is also oak. We have very efficient extraction and can always apply a wood protector if necessary. As you are looking for a budget refurbishment I think a white bath panel would be neater than the cream and I would just repaint those white filler marks. You could always have shelves on the wall above the cat loo with baskets for storage. You could do away with those freestanding towers making the floor much easier to clean.

I’d add a panelled bath panel in your preferred panelling style and paint in the plum colour personally, I think rick colours look great in a bathroom. You may be able to get something like this built cheaply for storage at the end of the bath and paint the top and sides in the plum and add a plant on top. Maybe a striped linen shower curtain, something with the dirty pink or plum stripe would be nice but have only found this one so far. i Can’t see above the rad but a vintage style cabinet would look great.I can’t see the size of the tiles above the sink but maybe stickers would work? A dirty pink might workon the walls or deeper taupe

Walls offwhite, towel rack, slightly narrower cat toilet (so it goes next to the bath).

I love that towel rack Rinked. 😁