Thank you for replying Adduxi 
It fixed itself after a few hours, I think it just needed to settle down for a bit, it's never happened to me before after all the years I been with Virgin Media, It brought back some very bad memories of being with another ISP, every time I got a power cut, the WiFi got affected so much that I had to leave
This is the fastest speed I got last month on m500 

This is the speed i got about an hour ago
