I have sorted out my travel / accommodation and it goes something like this…
Friday 13th September
Leave Birmingham to drive to Henley-on-Thames arriving mid-afternoon.
Park the car up.
Catch train to Putney Bridge, London.
Walk to Jury’s Inn, Chelsea.
Saturday 14th September
Taxi / walk ( depending on distance ) to Putney Bridge. *1
08:00 – 09:00 Start Thames Path Challenge.
Sunday 15th September
Arrive in Henley-in-Arden in the wee hours.
Stagger to B & B. *2
11:00 Depart Hotel.
Find car and drive home.
*1 I don’t know the exact start location but it is described as near to Putney Bridge.
*2 I have spoken to the B & B and they are ‘happy’ with my late arrival.