If you won't use it, then I would get rid of it. Otherwise, it just becomes something else that you will have to clean and, depending upon the dimensions, cleaning around the base of a free stranding bath can be a challenge. This may also allow you to have a separate enclosed toilet, double shower and/or double vanity (if you don't already have those), which may offer more practical benefits than an infrequently used bath. If necessary, possibly consider upgrading the bath in the main bathroom to a more luxurious size so that if you do feel like soaking in the tub, that option will still be available.

Kate's idea of using the pantry space is an excellent suggestion as a toilet can comfortable fit within 800 x 800 alcove with the end opening towards the bathroom and closing the extra door from the laundry toilet could allow enough space to squeeze in an extra handbasin but please double check all the dimensions ..measured from wall to wall the bathroom has to be more than 1200 x 2, the laundry more than 1200 x 2 and the toilet size isn't right or there wouldn't be enough space to open any of the doors??

We are literally having the same debate. We have a 12 year old and 9 year old, house doesn't have an ensuite as such but dual living set up with one bathroom on the ground level and one on the first level. At this stage we are thinking no bath...will be interested to see what you end up deciding too1

I have a glass screen for a shower bath combo. It’s attached to the wall with two hinges and a row of silicone at the base of the glass where it sits on the bath. I would say that a decent amount of the weight of the glass rests on the bath edge. So not suitable for your setup. If you talk to the installer, they may have wall fixing that run the length of the glass and hold the entire weight of the glass. You would still have water escaping through the gap.