86 ish yards depending on exactly where the tee is (a little further back would make 90, never played the place so can only guess where the standard tees are.
Strangely, it was 244yds from the back tee to the conservatory where Monty put his drive on day one (or was it two?)
I actually put it up as I wasnt sure exactly where the normal medal tees would have been. I know they dont extend round towards the 16th green really so put the marker where I did.