Until a couple of weeks ago I was getting ADSL speeds of about 8 - 9 MBs. But then I had an issue with slow ADSL speed, down as low as 1.5 MBs, which I identified and cured by changing the filter to a new one. Following this change I was then able to get 9 - 10 MBs for a few days but this has gone down in the last few days to a constant 4.5 MBs, regardless of time of day.
There is only one laptop accessing the internet most of the time, I have plenty of GBs available on my plan, the modem has the latest firmware and so on.
Is there anything else that could be causing slow speeds that i have overlooked?