As an airline captain working out of T5 at LHR it never ceases to amaze me how passengers know better than us how to book their flights. I often have to 'bite my lip' when I hear a passenger who has missed a connection - but only allowed an hour between connections!!!
Airports give a minimum connection time for VERY good reasons, yet too many passengers feel that they know best. There are a myriad of reasons that aircraft run late - and many, many of them are NOT the fault of the various airlines.
Transfer time recommendations are there for YOUR benefit. Please do not be surprised etc etc etc if you do not manage a connection when you choose to ignore info relating to connection times.