NEVER give you bank details unless you *know* who is calling.
That means either you called them or 1471 shows a known number.
Ask to call back in 2 mins then do 1471, I can guarantee the
number will be withheld.
If any unsolicitored caller asks for an personal details find out who they
are, if they are a "reputable company" then cancel any business you have
with them and tell them you will never deal with them again.