Thanks Keith. Your response confirms my initial inclination to leave it as it is.

Haha, Forest Hill's hotel. I got married there. No, I wouldn't put in a restriction. It's only a recommendation from the hotel owners to turn right, as the road that way is more suited to traffic and avoid a residential route. It's probably been put up to appease those residences.

Not even sure if you can legally enforce any turning from private land onto a highway unless a sign is displayed on the highway. 

We have a road close to where I am now that says Turn Left on the road, but there isn't a sign banning right turns nor is the word 'only' on the road which would also enforce the banned turn.