Thanks so much everyone, this thread has been very insightful! It seems the options are to spend £10k-£20k on a steel walled narrow boat to do up or forget the idea.
This is going to need some serious thought! It still may be preferable to throwing tens of thousands of the family coffers down the drain on rent, but it’s a large chunk to find.
Time for a good think….
My daughter is also off the uni this September, (5year vet course in Nottingham, fingers crossed). If we could get the boat ready in time for her second year then she can live on it too, perhaps with a pal or two. When she finishes her course, my son should be starting uni a few months later so we could sail it to his area. For my daughter rent is costing £170 a week, which we have to pay for 30 weeks of the year. We may still be quids in with a narrow boat.