I spoke to someone in their complaints team today. I nice honest chap called Gordon, and he confirmed that the link from my exchange (I forget the technical team he used), is flagged as Red (they scale from Green, Amber, Red and Black) in terms of capacity/utilisation.

Red means some congestion, but not enough to address, but black means they'll think about it, but that could well be 6+ months before the issue is resolved, apparently (planning, etc).

I've been given the option of leaving without a penalty, or sticking with the service receiving a discount. The vf shop is town is flogging the up to 38Mb service now at £20/month, so I can only imagine the service will get worse, and from the sounds of it fixing it isn't a fast process. Thinking I'm best off jump ship, but most likely I'll have to pay an activation fee as I'll need an engineer to make a physical change in the exchange for my line to move me off the vf equipment.

Paying a setup fee when migrating is normal these days, but you should avoid it If you find an offer doing free setup or reduced price setup.

Not sure why there would be a charge, that is a common misconception.

If you want to place an order, do not cancel via Vodafone, simply contact the gaining provider e.g. BT, AAISP, TalkTalk etc and provide them with your landline number, they will take over, this will automatically terminate your Vodafone service. It will generate a letter from Vodafone detailing any exit charges etc, if they charge you anything, simply contact them to ensure the agreement is actioned. At no point close or cancel down the Vodafone service with Vodafone Customer Service, as this will physically get the line terminated and you will need a new line which is more commonly chargeable and results in downtime.

BT currently have free activation, as do TalkTalk. I have not checked any others. You can order online via the website, simply providing your landline number during the order process. Vodafone legally cannot prevent the new provider taking over.