I'll try and answer all questions and clear it up.
Suresignal is a picocell - a small radio mast, you connect to the internet and power. Range ~20M tops.
Orange UMA/UniquePhone/SignalBoost is UMA - a system of routing GSM calls via the internet. Range equal to 802.11b/g/n
The difference is the picocell acts like a mobile mast, connects to the internet, broadcasts a standard mobile network signal (but with a restricted access list) whereas UMA is basically the phone connecting to Orange via 802.11x wifi and thus the internet and having calls routed over that.
Therefore UMA requires the handset to "understand" UMA and how it works but any phone can connect to a SureSignal - the phone doesn't even know it's not a standard network mast.
UMA is handset
and network dependent - Orange is basically the only network that does anything with UMA currently and the handsets Orange stocks reflect this a lot of the time. While any UMA handset can technically link up to any network which supports UMA, in the majority of this forums home territory you will only see this at Orange but it is controlled via handset config files.
SureSignal is network dependent for a very good reason - it contains a cryptic code function to tell the network it is a genuine Voda SureSignal instead of a fake one because if it was a fake one it could listen in on all your calls
It is not handset dependent though as explained above.
If you have low voda signal and are on £35+ "apparently" you can just ask for one and you'll get it, lower than that you pay a fee (£25/£50, this is sold at a loss obviously but you'll receive and make more calls so a net win for the network)
GSM repeaters are another thing all together but it's pretty obvious what they are (and good ones cost 4/5 figures so I doubt this is a home thing).
