Thames Water do not think that there is a problem with drains in the area. However, several instances of them being called to clear drains which were leading to localised flooding suggest otherwise. It is therefore up to residents to report all localised flooding every time it happens.
The sewer flooding questionnaire from Thames Water should be filled in to record every event.
Please also see Flooding – Hillingdon Council. This site has lots of links about responsibilities, what to do to prepare yourself and your property, as well as who to contact during a flood event.