René Bull's wonderful sketch was made from a koppie where Three Tree Hill Lodge stands today (despite the lodge's name, TTH itself is 2 km away to the north-west). Artists approx position is GPS -28.662, 29.487. The crowds of reinforcements on the southern (right) part of the summit is accurate, as is the observation that the Boer shells mainly fell on the southern (right) part of the summit, and the British shelled the north (left) of the high ground. Parts of the long grass on the slope of SK look as if they have been recently burnt (the grass fire was described on 20 January).
Here are some errors I think I see, though I am often wrong:
1. The battery of six 15-pdrs firing shrapnel from this position was the 19th Btty (not 78th Btty, which remained in position on TTH).
2. The postions captured by KRR were the Twin Peaks (GPS -28.649, 29.537 and -28.648, 29.545) neither of which were visible from this spot - and thus of course not visible to Gen. Warren, either. The Twin Peaks had no name at the time, and were labelled Spion Kop on the British "Blue Map". The KRR were not shelled as they attacked. The feature shown in the sketch is nowadays called Conical Hill though at the time it was un-named or called the "northern extension of Spion Kop". Conical Hill was indeed shelled by British shrapnel, leading the Boksburg Commando to abandon their position mid-morning. The Connaughts did express misplaced concern that British troops were there and hence under friendly fire.
3. "Our shrapnel bursting over Boer trenches" - there were no Boer trenches on SK summit, though there were Boers directly under the shrapnel bursts - and outlying British soldiers too, if they are shown correctly. However, the skyline here is sketched inaccurately and it is possible he's drawn Conical Hill twice.
4. "Boer trench captured by us" indicates more-or-less the position of the main British trench - but there was no "Boer trench"in that position.
Thanks for sharing your unique sketch, and congratulations on finding it!
Rob