As the o/p only referenced the Daily Telegraph in the text of post with no actual link, I'm making the above, consistent, report by Mechanic and his wife the gospel on the van's breakdown.
The Broughton's statements have not wavered in print or in video during numerous accounts.
I'm quite certain the Mr. Broughton would have counseled Lucas on the nearest shop capable of replacing a cracked cylinder, and helped him arrange for the towing. This also could have been the end of their journey-- at least in that vehicle.
They left the couple confident they had things under control.
I think they are solid witnesses.
MOO