We used to find that the 737-200's used to make a tech stop at Cardiff quite often an their way from Malaga to Dublin.
Why would they need to do this?
In the 1980s I flew (as a pax) several times from Bristol (BRS) to Tenerife South (TFS) on Britannia B 737-200s and we never had to take on fuel en route in either direction.
BRS-TFS is a far longer distance than AGP-DUB, isn't it? And we were leaving leaving BRS's short and high runway
This is a genuine question from a non-aviation person.