I have a very preliminary report which is.... the set doesn't work at all indoors, behind a patio door with two 6mm non-metallised glass panes.
What side does your patio face?
The Thuraya satellite is in geosynchronous orbit at 44 east (according to Wikipedia), so from the UK this means that it's somewhere in the southeast, approximately 30 degrees above the horizon. I would imagine you have to have a reasonably clear line of vision in that direction to get any reception at all. Particularly since the handheld unit, as far as I can see, does not use a directional antenna.
OTOH, Thuraya claims to have roaming agreements with a lot of GSM providers so if you're in reach of a GSM network (and in Europe, it's rare not to be) your calls will be handled by the GSM network instead of the satellite. But, IO, I assume you know that and deliberately turned that off to test the satellite performance?
The advantage of Thuraya - if it works - is that it is a much better deal cost wise than Iridium.
That does not surprise me all that much. Technically speaking, the Thuraya system is inferior to the Iridium system, especially for voice calls. Latency is far worse with Thuraya than with Iridium and with only one satellite operational, coverage is not truly global.
However, for most applications Thuraya is good enough and with the higher bandwidth available, may be more suitable for data connections anyway. And the roaming agreements with the GSM providers is of course very clever. I have no doubt that Iridium would want to do the same thing nowadays but their handhelds are simply not capable of doing this.