Seems this was the "killer" route card and thereby the one with hint overload. It wasn't meant to be. This was a big surprise to me.
Clock times at junctions were always a popular navigational exercise (arrive at the hour, leave by the minute or vice versa). This was "just" an extension to grid square exit times based upon a square clock (Top left corner = 10:30, Trc = 01:30, Brc = 4:30, Blc = 07:30). To be awkward some of the times were decimal. Many got the (Times) New Roman hint from the title and font, but then had problems applying the values. Most were clean after the hints.
The times were accurately calculated according to where a road exited a grid square. If you were a bit lax at the end you may have missed TC5 on the final loop.
The hints were: 1) Departure Times 2) Grid Square = Square Clock 3) Note: Decimal Hours and Hours:Minutes.
Best performance: Ewan Leeming 35:49.