No internet

[Sy15]

Internet speed has been slow for over 2 weeks - flags that there is an issue to begin with - but checking on here to try and fix has suggested everything is fine - as long as my phone isn't linked to the internet while checking. 
tried restarting switching on and off  but starting to get a little frustrated - an expensive service to have slowing to a crawl and eventually stopping completely. 

[caesarome]

@Sy15 

It isn't not clear from your post what you have or have not done so try running the line test here to see if any faults are found:
https://www.sky.com/help/articles/broadband-diagnostic-start

You can also run the test via the MySky app on a mobile data connection.

After this has finished and if it reports back all is good click on broadband to run an updated test. If you get amber or red please follow the on screen instructions.

If this is of no help give Sky a call to report it to them.