Hi Simon,
Yes we do have a minimum speed guarantee.
The guaranteed download speed is 50% of the advertised speed of our service on the date that you placed the order and is set out in the speeds table we send you. You need to keep your Virgin Media Hub plugged in, switched on and set to enable us to obtain speed information from it, which will help us to diagnose any problems.
This speed guarantee is for the speeds being delivered to the hub.
Was that speed test done on a hard wired or Wireless device please?
If it was wireless, please do a hard wired test and post the results.
Please pop back to us when you can,