Wife’s mother’s internet was acting weird – it seemed a bit like a DNS problem – slow or partial page loads – but not that DNS problem as she is on the wrong version of Mac OS and Safari to have that problem. And it affected Firefox too. After changing DNS servers and other fiddling around I decided her ADSL modem/router must be faulty so I ordered a basic replacement.
And it fixed the problem. That’s the second ADSL Modem I’ve seen go funny after a couple of years and start giving odd faults.