On 28 Dec, 12:23, stuart noble wrote:

Could you install a service valve on the supply & leave it partly closed to
reduce the incoming flow?

There's already such a valve, and this is what I've done temporarily.
Can't say I regard it as a good long-term fix though,

Nothing in the Fluidmaster itself I suppose? ISTR a flow reducer plastic
thing that you reversed for mains pressure.

Can't see anything like that - there's a simple scale filter, which is
in place.