This reply I got from Tibs is satisfactory:
"... We regret to learn that you did not have a
comfortable ride on our bus service, 854 and would like to
apologise for it. We would be scheduling the bus, TIB 1015 back for
an immediate rectification. At the same time, we would be
conducting checks on the rest of the fleet progressively ..."
Glad to know that they will be checking the whole fleet of Dennis
buses.