It would appear likely that this Sandra Elizabeth INGRAM (Lady Hill) is the one whose birth was registered in Roseneath or Rosneath, Argyll and Bute (ref 502/17) in 1944. This is borne out by the fact that
http://www.thepeerage.com/p44068.htm#i440671 gives her father's name as John Crosland INGRAM, and that a man of that name married Elizabeth Valerie ANDERSON in 1943 (ref 644/8 1412 - Blythswood). The fact that one of the executors of a Elizabeth Valerie INGRAM, who died on 13 September 2005 (see
https://www.thegazette.co.uk/notice/L-57980-040), was Lady Sandra Elizabeth Hill seems to provide further confirmation.
Walter Henry Rupert WILKES was, per company records, born on 19 December 1958.
James Robertson McNAIR (1923 - 31 VII 1986) married Maud Christian DICKSON (1919 - 16 I 1997) in 1949 (ref 768/12 - Peebles).