Ask on frequency the reason for the radar vectors if you have not been told. We are required to inform you why you are being placed on a heading, and if I'm not too busy I will give you a big long winded description of all the relevant traffic to affect in your area, and so you might regret asking in the end.
Only thing I will say it's never for no reason, because headings are more work controller side, and personally I take aircraft off a heading essentially the moment the lateral/vertical separation is increasing again. Travelling up through the spine of England as others has mentioned, will have you conflicting with a massive amount of inbound/outbound and overflying traffic. It's a busy sky at the moment.