A word of warning... the UK site is operated by a company based up near Derby, and often go by the name carputer or mannocks.
They ARE NOT TO BE TRUSTED,
If you do buy the grom kit, order direct from the company in the US, or through one of the partners in other parts of Europe... Carputer are a bunch of lying, deceitful and untrustworthy C**TS. Grom themselves were very helpful and even sent me a replacement lead for my accord from California whilst the UK reseller was trying to gouge me for loads more money for the replacement parts when the original ones were faulty.
In the end I had to resort to making a claim back through paypal and returning the entire kit simply because they wanted me to pay them to replace faulty parts when I'd only had the kit a few months.
I would never, ever buy anything from that bunch of cowboys.
As I said.. Grom themselves are great, and I had many discussions with them about my problems, which ended up with them sending a replacement part out from the USA 5000 miles away when Mannocks were 40-50 miles away and wanted me to pay them for replacements. Don't support companies that try to rip you off. I even signed onto groms beta test program and gave them feedback about how to improve the software for diesels.. specifically the way the diesel requires a pause between insert key and turning the engine on for the glow plugs to warm... Their system connected the bluetooth immediately, which then lost the BT connection when you started the car... as the grom unit resets along with the car system... whilst the phone is disconnecting from the unit, it cannot receive the signal to reconnect... So doesn't... and you then have to manually connect the BT.
All of that could easily be resolved by simply inserting a delay in to the software, so that BT devices don't connect for say 20 seconds after it starts up. Which is about the time it takes to get in the car, put the key in the ignition, start the engine and do up your seatbelt... Hey presto, problem solved.
But as I had to send mine back because, I wasn't about to have it replaced by those con merchants at mannocks/carputer and got a refund instead... I just lived without BT as I'd tried a few BT transmitters, but quality was poor... and my replacement car has BT installed now... and even if that fails, I'd get a Parrot 9200i kit installed rather than a grom... simply because of that bunch of arsehats.