Good point - I am certainly planning to ditch the ELCB anyway (space is
a bit limited in the cupboard) so that is not to much of a problem to
replace it with an RCD first.

Make sure you replace it with a 100mA time delayed RCD. Your socket
circuits/outside electrics etc. should have additional 30mA instant acting
types. I would definitely continue to use a separate 30mA RCD for the
workshop compared to the house electrics.

Christian.