You seem to have some noise on the line this is shown by the post RS Errors, in cases like this I would recommend going around and check that all coaxial connections to all VM equipment are finger tight, once that has done power off router for 30 secs and then back on.
If after all that the Post RS Errors keep rising then an engineer will be needed to find the source of the noise.
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Tidied up the cabling behind the TV, it had got a bit messy. Made sure the coax has nothing wrapping over / round and made sure connections are tight, the errors seem to have gone away and the speed has increased a little (68Mb), though ping on speedtest still highish at 20ms.