The message
from Dundonald contains these words:

Just had an extension and new fuse board fitted as a result. One of
the plug rings keeps flicking the fuse switch on the fuse board when
there's a bunch of appliances running off it in the kitchen, the usual
stuff - kettle, washing machine, dryer etc ... I'm gonna talk to the
sparky about this but I'm wondering 1. why this might be happening and
2. if there's a possibility to increase/decrease the tolerance level
before the fuse switch flicks?

You really need to give more information but:

Are you sure it is a ring circuit, not a radial. Rings usually have 32A
MCBs, a radial may only have 20A MCB.

What are the appliances on the circuit and what do their individual
ratings add up to. 4 amps to the kilowatt should be close enough to see
how highly loaded the circuit can be.

If the capacity is marginal you can avoid tripping the circuit MCB by
making sure the 2 highest rated appliances are not in use at the same
time as every other appliance on the kitchen circuit.

--
Roger Chapman