There's nothing wrong with your downstream stats, they are all bang on spec - you also don't have any errors there.
Your upstream power levels are too high - beyond the recommended max of 50, but only just - you may struggle to convince VM that this is the cause of your woes..
a few T3 timeouts is normal, you're getting one every few days - not convinced that this is going to be the root cause of your problems..
a couple of RCS partial service messages, indicates that a channel is dropping, a lot of these is a cause for concern but they were clustered around 11/12/13th and nothing since.. something to keep an eye on though.
I'd recommend that you set up a BQM to graph the quality of your connection as seen from the outside, and see if the link drops at the same time that you experience issues..
It could be that you are in an area that has heavy utilisation - the BQM will help highlight this
Its also worth calling 0800 561 0061 - an automated service status line, see if there are any area issues.