This was discussed about the 13th at Liphook on another thread not so long ago.
If the pin is anywhere but tucked in behind the left bunker the best angle to approach the green whilst playing from a flat lie is from the 12th fairway. Most of the 13th fairway slopes fairly steeply from left to right after about 250 yards-ish. As a reachable par 5 with a long club in your hands going for the green in two it is a tough shot from the canted 13th fairway. Personally I don't think the shot is really on to hit the 12th fairway from the tee but if I find the heather up the left hand side of the 13th fairway, which is fairly often as the left side is the best place to be as it is a touch flatter than the rest of the fairway then I'll pitch out onto the 12th fairway to give myself an easier 3rd. Ben Stephens claims that the play to the 12th from the tee is on and plays the holes that way. If you play short enough from the tee you can gain a flat lie, but you leave yourself a long way into the green. For the shorter hitters not able to reach in two, playing their second out to the 12th is definitely a good option.
A photo from behind the 12th green looking up 13 from James Boon's photo tour of the course.
You can just make out how the 13th fairway drops away and see the flatter 12th fairway.
From the tee the 12th fairway to the left is partially blocked out by trees, unless a big hook/slice for the lefty is attempted. Photo from Sean Arble's photo tour.
From behind the 13th green looking back up 12 and 13, photo from Brian Sheehy's photo tour.
Both Brian's and Sean's photos clearly show the slope of the 13th fairway.
The 15th at Liphook would also be better approached or just plainly shorter if played up the 16th, but the club introduced an internal o.o.b., some new trees and a new greenside bunker to stop the play for H&S reasons. It seems like a rather awkward hole, though not bad it's probably the worst on the course imo.