Hey there, don't know if this is a bit late? (from MCSA KZN section route guides)
Rated Grade 17/18 unless you use the aid on pitch 5, then a 15/16.
Have no personal experience but will be able to tell you more after Feb11th as we're doing it guided then.
SENTINEL: Angus-Leppan Route (F3 or F1/A1)
(Map #1 : G:23 : 3165m)
Opening Party: Pam and Peter Angus-Leppan.
Date: 17 February 1959.
Time: 3 hours climbing from the contour path to the summit.
This is a very popular route, being sunny and exposed on fairly good rock. Although easy, it is not recommended for beginners, as the consequences of a fall could be serious. This line on the huge north face of the Sentinel used to be known as the Gendarme route and is one of the best routes in the 'Berg at its grade.
From the contour path, head for the right hand side of the large gendarme at the base of the north face. Scramble up the gully formed between the gendarme on the left and the main face on the right. Continue up the gully to a 5m rock step that blocks the gully. This blockage may be passed in one of two ways. Most people follow an easy, but unprotected zig-zag line (D) on the face of the gendarme, to the left of the blockage: Climb up 2m, traverse left for about 10m, up for 3m, and then back right for 20m (a bit thin for the last few metres) to a position in the gully at the top of the blockage. Alternatively, you can rope a pitch up the right of the blockage (F) - this is particularly tricky when wet. From the top of the blockage, scramble up to the nek between the gendarme and the main peak, climbing through an easy rock band on the way.
1. 20m D. From the nek, climb up easily, heading diagonally left and belay on a good grass ledge below a short steep wall.
2. 20m E. "Grotto Pitch". Climb the wall to a small, vegetated cubbyhole, with one awkward move on the way. From the cubbyhole traverse to the left for 3m. Continue up an easy section for 10m and into a short grassy gully. Belay near the base of an open book / large recess(*) and adjacent to the start of a good rock ledge the runs off to the left. (*) = See variation below.
3. 25m E3. Traverse left along the rock ledge (exposed) which leads around a corner and then up a narrow ramp. Belay at the top of the ramp adjacent to the huge recess that splits the north face. Take care in setting up this belay, as some of the rock is loose.
4. 15m F1. Traverse to the right across an exposed slab, using spaced footholds, and continue on to the corner. Climb up and belay at a large block on the ledge above. From here, climbers following the leader can be safely top-roped across the traverse. The only significant gear for the leader during the traverse is a 3½ cam in a crack at foot level after 3 or 4 metres.
5. 35m D. Traverse to the right along a good rock ledge for 20m, crossing a recess and continuing around a corner in the process. Climb easily up to a belay on a large blocky ledge.
6. 5m F3. Move up into the cubbyhole a couple of metres above the stance. Clip a good peg under the roof of the cubbyhole and then, at the highest point, reach round for a good hold and use this to move diagonally up and right through the overhang. One intermediate sloping hold is needed to stand up and reach good holds. This pitch was originally aided up a line a couple of metres to the right of the cubbyhole. It is also possible to climb this short section further to the left of the main cubbyhole. From the top of this pitch you can walk to the right along a broad ledge and join the topmost part of the standard route. Alternatively, complete the route as it was opened, by climbing the final pitch.
7. 10m D. Climb the easy chimney in the rock band above the previous pitch and then stroll across to the summit cairn.
Descend by the standard route.
Variations: Pitches 3, 4 and 5 can be bypassed by a direct route of two pitches that follows the open book / large recess near the start of pitch 3. Although somewhat quicker, this line bypasses the best pitches on the climb! Angus-Leppan's original Journal article makes reference to this open book as a, "particularly evil looking, green chimney . . . narrow, choked with growth and smooth sided." but Dodding claims that it has been cleaned and is a reasonable prospect using modern climbing gear. The details of this variation are as follows:
Opening Party: Russ Dodding, Chris Lesley-Smith and Steve Kelsey. Date: 7 August 1998.
Pitch "3". 27m F3. Ascend the groove (unprotected at first) to an obvious traverse line at 8m. Step delicately right, traverse around the arete and walk to the right along the break to a large stance next to a gully which is on the right.
Pitch "4". 20m E. Climb the arete easily to the blocky stance at the start of pitch 6 on the usual route.
There are also other variations to the start of the route. These all begin lower down in the gully but all end with much the same pitch 6.
Ref: MCSA Journal 1959, pg 104.