I actually got a quote directly from CLS a month or 2 before for about £300-400 more than BRC quoted me but they assured me that if I booked the car in via themselves the price would be honored.
My engine is a BMW N62 4.4 v8 @ 333bhp, I previously had a 745i converted with a cheaper stefanelli system for £1500 which wasn't great (Warning lights on all the time and injectors couldn't keep up with the engine demands at high load).
I had the car converted for just shy of £1900 with a free courtesy car while my car was converted - Dropped it off on Monday had it back Friday evening.
I've done about 1400 miles now on LPG and the BRC system seems to cope much better. The car was checked by CLS at about 1050 miles and everything deemed to be okay.
Haven't had a single warning light even after a round trip to London via Banbury from Newcastle-upon-Tyne and the fuel trim looks good which is a big thumbs up from me!
The install is neat and tidy too, the only thing I didn't get was my filler cap painted but I'll get that done myself or when it goes for servicing.
If people are interested I can take some pictures of the install.
Also they fixed my sticky bonnet latch on the passenger side for free
Overall I am very pleased with the job and would definatley recommend them.
Hopefully someone finds this useful as I found it hard to find anyone really around the north east with recommendations!