Red light on hub 3

Solid red light instead of white, tried rebooting several times and doing the pinhole test, Internet seems to be working bur does drop out alot. Don't think it's an led issue as when it's booting up green appears in it. Doesn't feel overly hot at all and is well ventilated. I spoke to someone on the phone but it was a nightmare getting through and took me ages. Tried everything they suggested but it's still red and giving me anxiety as I worry it will over heat, its about 5 years old! @virginmedia can you please advise? I think it's time for a box. Thank you