Great ending

After 4 great days in Lisbon webiard a slightly delayed flight and Land back in Gatwick at 11pm. Whilst travelling on the M25 we hear a loud pop and the car informs us we have a rear tyre problem.
That was nearly 1 and 3/4 hours ago and were currently cruising at 40 mph on the M4 with still 70 miles to go until home. We have exceeded the recommended 50 miles on a 'runflat tyre' and have fingers and toes crossed.