I've located your account and there does appear to be a high demand for our service in your area at the moment under the fault ticket reference F004193000, with a review set for 24/05/2017. With this, you may find that your Virgin Broadband is a bit slow and your TiVo® BBC Iplayer programmes buffer at certain times of the day (if applicable).
Thanks for getting back in touch, I am sorry to see you have continued to have trouble with your connection.
We do not throttle bandwidth, looking at the fault the increased demand seems to be indicative of the times people either come home from work and school and when people start to go to bed. There does seem to be a decline in demand starting from about 11PM so come midnight the connection should be back to good speeds. This will vary from day to day.
I hope this helps to explain the issue a little more.