Hi folks, Apologies to Tugg and LIzzyfan that I did not come back to this chat before it was closed (I am new to this...) I have not tried the Forte Anti crystals as was not prompted for an ad-blue top-up / refill, and was minimising mileage until replacement parts came through, which took 3 weeks!! I will try the crystals going forward. Like Lizzyfan, I have gone for replacement as l really like the car and anticipate keeping it for a good few years. My replacement was £2,235.50 +VAT so pretty much the same (parts £1,867.00 / labour £368.50) Hope this helps. Cheers all, Dave A.