This happens to me every so often. I go through the process of downsizing and living frugally. Fast forward 9 months and I am throwing money at people in the street. Very hard to keep at it, especially if you get a windfall or some unexpected cash along the way.
Open a debit order with Satrix etc etc then its effort to cancel the thing and you will live with whats left. If you really need money you can always take it out again.