I was briefly a member at Knole Park when I lived in Kent and have a copy of "The Story of Knole Park" which was written in 1989 by a former captain, David Boe. It answers a few of the questions raised in this thread, although not for everything. From what I can glean:
James Braid was asked to prepare a preliminary survey before the members broke away from Wildernesse. It was in September 1923 that Lord Sackville, who owned Knole Park agreed to allow a golf course to be built. In a Special General Meeting held in October 1923, where they agreed to break away, it was mentioned that Braid had consulted on the feasibility of a course on the land. Abercromby was consulted for a second opinion a month or so later. Of the two plans, the owner of property, Lord Sackville, favoured Braid’s because it called for the felling of fewer trees (not the other way round). It is not clear why Abercromby’s was chosen.
here is no mention of the clubhouse being by proposed as being near the 5th tee. Abercromby’s routing started from the present 1st and was provided to the club in December 1923. There is an inference that the other routing (Braid’s) is reported to have started in the same spot and was the reverse of the Abercromby version. It was always part of the plan for Lord Sackville to build the clubhouse and rent it to the club.
Regarding the opening match, George Peacock was the first professional at the club and Andrew Peacock, also a professional, who played in the first match was his brother. Dan Peploe was a scratch golfer and head of the greens committee when the course was built.
The 4th tee was originally on the ledge below the 3rd green (on the left). The drive for the 4th was over the hillside called Spion Kop and was a very long carry over bracken. Instead, many, especially the ladies, ended up playing back down the 3rd fairway first, before turning the corner so they decided to build the new tee where it is today.
Although Abercromby laid it out as a Par 72 (6 of each), in the early years it was wet and so the 3rd, 18th, 6th and 14th were, briefly, par 5s as the course played so long. This was changed back to a Par 72 over time and remained that way until 1965. Contrary to Abercromby’s routing, the original 18th tee was almost as far back as the 2nd green with stray balls being hit directly over the 17th green. This was when it was a Par 5 but it was shortened soon after opening, and reverted to a Par 4, for safety reasons.
The 15th green was originally on the ledge below the current green before being moved back in 1965 by 30 yards to its present, blind, location. This was in order to add length in order to make it a Par 70 as the English Golf Union rated it a 69 under their new rules at the time. New tees were also added at 7, 10, 13 and 16 for the same reason.
There is no mention of any changes to 6th or of Tom Simpson. However, around the time of the war, and c15 years after the club opened, G Simpson was secretary at the club.
I hope that helps fill in some blanks.