A quick look on the VM website says that the cheapest Sky Sports package is £38.75 a month, so it looks like they were offering you movies for £2.25 A month.
Movies are listed as being £21 A month (think it's £20 on Sky), but their is a standard offer of £10.50 for six months (£9.99 on Sky).
On the face of it it was a good offer, but I still don't think their offer was worth it overall. Wonder if you could ask for movies only for £2.25 or even less?
The official policy is that retentions cannot offer movies for less than £7 A month, but this seems to have been abandoned