ice to see everyone is so bothered to slag me off and put me down
That's pretty well how it is sometimes unfortunately. Nothing wrong with the way you write English (as if you're speaking) and doubtless if you want to write a very correct letter you can do. Also, you may be a great teacher - the ability to make people learn is a real skill that's partly innate. Some people can do DELTA, MTEFLA, whatever and still be crap. Others can have left school at 16 and be very good at it.
As for Brits teaching English in Poland, right now there are too many people chasing too little work, bad feelings from professional teachers who feel they're undermined by less experienced people accepting low wages, and an ever-decreasing pot of money.
Adam, why not advertise your services on OLX or something like that? Why work for a school when you could do it alone?
Yes, but watch the tax office with that one - they sometimes pretend to be interested in lessons and entrap people. Happened to someone I know.