Hi bob60. Ok, the F5000 is a normal [non-smart] TV and then you would be considering a Samsung Blu-Ray player. From my understanding, the F6500 is the minimum Blu-Ray player that has all the UK catch-up services.
I haven't personally tested this model to see if it can change app stores, but I am reasonably confident it can. In any event, if you go for this, make sure you keep the packaging in good nick, just in case it doesn't work and you want to send it back - this is important, as for all we know, Samsung may change their firmware between now and when you buy and then it can't be changed, or your ISP has issues with Smart DNS. Both are probably unlikely, but it pays to be prepared.
In any case, you may want to switch to Overplay's Smart DNS before you get the new kit. It is possibly cheaper than your VPN service [you only need their Smart DNS sub which costs US$4.99 or 3.60 per month, not the full VPN] and test it on your laptop. You should get a better quality stream as Smart DNS does not send all traffic through a virtual tunnel. Also, it will test that everything works before you buy new stuff - remember, a VPN won't work with the Blu-Ray player, only Smart DNS.
Secondly, there are other options....
If you have an iOS device, you could just get an Apple TV and use AirPlay. The BBC and ITV will happily airplay over to the TV then, and you could use Zattoo under a sub which works amazing [requires Smart DNS as well as the sub].
The amazingly cheap Now TV from Sky is a cheaper alternative. It will only set you back £10 and you don't need a Sky sub. At the moment, Smart DNS only works with the BBC iPlayer, but there is the prospect that it will work with Demand 5 soon, and hopefully 4oD when that comes on the device. The catch, you need to set Smart DNS up on your router which is easy, but you probably need to consult the manual for that.
[Reviews on Eye on-demand for the Sky box [under hardware] and Zattoo [under live TV] if you want to look them over]
Finally, 2mb may be ok for the SD streams, which require 1500kbps. I think the iPlayer offers a lower 800kbps stream for emergencies. But it could be a reason to upgrade - the higher the better.
Anyway, you can test it out first on your laptop or even smart phone.