Glos Guy I think you may be very disappointed with the 3 series touring if interior space is a priority. The X1 has a larger boot space and based on my comparison of both cars the X1 is roomier and easier to ingress and egress due to its higher seating position.
My 3 year old 20i X-Line X-drive has been a revolution as I never ever thought I would get attached to a car like I have the X1. Its boot is quite voluminous with the ability to remove the boot floor covering for extra depth as well as slide the rear seats forward. Fuel economy has been the biggest surprise when during summer 2019 I achieved 54mpg on a run down to Cornwall loaded with 4 adults and a bootfull of neccesities for my holiday. The online computer was indicating a theoretical fuel distance of 804 miles with the fuel I had in the tank.
If it was not for the AP doubling in price I would be ordering another one!