OK, since you are in the UK and Wendy says you probably only have 1 full bathroom I would stick with a tub but have a really nice shower head installed over it. That way you get both and the lack of a tub can cause problems for many people.
I take showers exclusively but I live in the US and have a master bath with stall and guest bath with tub. There have been a handful of times in the 21 years in this house that I have needed the tub. I will be blunt about this. On occasion I have had hemorrhoids and HAD to soak in a tub. Also the same with a sprain leg muscle soaking in the tub was great. So for medical reasons sometimes a tub is necessary.
Hope this helps but in the end the decision is what will make you happiest.
