Hi Mike,
thanks for the info. But...are you sure? Which is your source? Could you write here the names of the retired riders for that race? They are:

no. 17 Roy Richardson
no. 51 Ettienne Godart
no. 25 John Donnan
no. 49 Fabrice Miguet

All these retired during the 2nd lap.
Who are the remaining two retired riders (1st lap)?

Many thanks,
Marco