There were these two crashes here actualy in the Bosworth Hall grounds -
As far as i can work out i don't think there was ever an incident involving a Lanc taking off or landing at HB. The only local crashes involving HB aircraft (aside from the two in the link above) were Wellingtons. One crashed on the 24th of September 44 at Althorp Park in Northants killing all on board and there was another HB based Wellington lost after it had to make a forced landing at nearby Market Harborough airfield on the 3rd of Feb 1945. All other Wellington's from HB that crashed occured many miles from the airfield or Leic or Northants.
Maybe your dad was looking at local WW2 aircraft crash sites in general and not actually involved with HB as there were quite a few in the area.
Hope this helps,