I do this a lot, all over the country, and I always go for a Holiday Inn Express. Forget Travelodge and Premier Inns, they almost all have security doors that require key access. Holiday Inn Expresses tend to be free access until around midnight.
Be wary of sellotaping door locks back, if you are caught you will told to leave.
Cheap motorway service station hotels are as equally hot for getting ample fucks, especially if near a lorry park. Always a few married guys needing to unload.
If in doubt phone the hotel and ask, just say you have had things stolen from a hotel room before and want to know about the security.
And ALWAYS get a room with a safe and lock your wallet, car keys, mobile etc away.
Have as much fun as I do chaps. 🙂