Monoprice.com ships to the UK, I asked them last year.
Contrary to folklore, all HDMI cables are not created equally and they do NOT all work the same.
Monoprice.com features low cost cables, that may offset shipping costs, but all of their stuff is really high quality.
My problem with MHL-HDMI is that ive had 3 adaptors that didnt last more than a month.
Wth mate?!
The one I got from monoprice.com has lasted me nearly two years and it's seen a lot of use. Less than US$15 with shipping, toss in another $5 for the 11 to 5 pin converter that Sammies need (and of course adjust for currency and shipping).
As for point-to-point streaming, DLNA does that no problem, part of the spec. Except good luck getting codecs to work with TVs or other clients regardless of price.
The only devices I've heard working as advertised - iow, simply - for device streaming are the HTC and Samsung mentioned above and the Apple TV.
Along with the curse of vendor lock in on your device choices. I don't see that changing because it's not in their interests to not behave that way.
You might also want to take a good look at the Roku products.
Not perfect and relatively new to device casting, and they go through your router as well.
Codec limited like other general solutions but still - Roku is pretty good ok.
http://blog.roku.com/blog/2013/09/09/roku-android-app-adds-video-streaming/
See also Juice for Roku in the Play Store.
I don't have the answers, just saying what the options are today.
PS - how we cast our phone videos of the rugrats to our TV: upload to YouTube and just cast.
Simple trick but for people just looking to cast personal videos, there you go, and no codec and software headaches.