If you do get accepted ny NATS, don't expect to be posted to Stansted; it's 'pot luck' you might not even be posted to an airfield.
If you're trying to split bringing up kids with a career in ATS, you might find becoming a FISO would be better for you. You would need to self study for the written exams, initially for an Air/Ground Radio Operator Certicficate, (a pre requisite for FISO practical training) then take the written for FISO, then start training, 40 hours minimum before you can operate solo of which you can only claim 4 hours per day towards the 40.