With a bit of luck my last question...
Would a hired power flush from HSS (£87 for a day) be likely to solve this issue?
No watch?
No cup, no saucepan, no measuring jug or even a plastic milk bottle?
Joe-90 can measure the flow rate from a tap!

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local