More reasons not to drink that stuff!

Yes... And no.

You can now rectify gin without any licenses, so can do it at home. You would need to buy duty paid spirit.

If you are making spirit from raw materials you need approvals from HMRC.

The actual process of distilling js not complicated. The approvals can be.

Yes. There have been a couple a bottlings that were a blend of cheap Scotch and Irish passed off as English. Not common, but it will prevent running into problems like the Japanese have where most of their 'japanese whisky' was actually Scotch.

The definition of single malt is consistant with everywhere else in the world (including Wales) except Scotland. The SWA are upset because England will allow mashing at a local a brewery instead of being at the distillery. They say the whisky loses it 'sense of place' - except scottish distilleries buy their grain from Canada and Poland and mature almost everything in a huge warehouse outside Glasgow -hypocrites!. At least the English GI unsists on UK grain!