As a representative of your local "Bank of Mum and Dad" branch i can confirm that i provide funding equal to £150 per week during University Semesters. So 32 weeks at £150 a contribution of £ 4,800 this being in addition to the maintenance loan per year. This is for a student at University of Bristol that is not working any part time jobs whilst at University but does work during the summer holiday period. This is at the top end in relation to most students.
Online reports i read tell me that the average Bank of Mum and Dad payments are £37.50 per week during University Semester time in addition to the maintenance loan. However, colleagues at other Bank of Mum and Dad branches that i am in regular contact with tell me that they fund between £50 and £150 per week. The lowest being £50 per week BUT this is from a fairly affluent full time employed parent demographic. I appreciate that many students are not as fortunate.
My view would be that if you have calculated that you have £19 per week after paying out accommodation you will need to add to this in some format either by bank of mum and dad or some other means. If your local Bank of Mum and Dad branch is closed or wont offer any financial support then you will need to pick up at least a few part time hours per week to sustain. Many students do this and there are plenty of opportunities close to most universities.
If you think about it, if you managed to get by on £6 a day which is fairly tight that's £42 a week so if you only have £19 you will need to top up by at least £23 a week but most students want to attend events and buy tickets or pay for sports or clubs so you need something for that. You will do Ok just need to learn to budget well and take advantage of all the student discounts you can to help keep costs down,
Good luck