Probably the easiest way might be to ask for copies of your bank/CU/CC statements for Mar/Apr/May. Very hard to be cash only these days. If you are one of those lucky few who are cash only, I'd imagine SW would tell Revenue and you'd be on short list for an audit next year. Good luck trying to claim your fuel/M50/carwash/whatever expenses against your income when it comes to it.
When I stopped, I printed off a receipt (with date & job number 001). When I restart, I'll print off another receipt with new date and job number 002. Unless 'they' can prove I tampered with the tamper-proof meter, that'll be my proof I didn't use the meter for the last month or two.