siamp diaphragm - Simple repairs to a toilet filling valve. No plumber.

no plumber required.
Replacement diaphragm cost £4.45 from screwfix, or £2.70 from amazon if you can wait for delivery. Repair only took a few minutes. Interestingly enough the local water company has been doing repairs so there may have been a blip in water pressure.
No tools were harmed in the making of this video.
The b in plumbing is silent, plumb is the Roman word for lead. Old water pipes were made from lead, hence the term plumber.
I hope this will help someone, a typical call out for plumber starts at about £80.