Mark 2013 XJ LWB

Hi all. Hope everyone is healthy and happy. Could anyone suggest an engine rebuild or recon business for my 2013 XJL? A timing chain snapped and despite paying £2000 to try and fix via the garage, it's running but not on all cylinders. I'm looking for a trustworthy place. There are alot of places that advetise and alot of bad reviews for some places. I understand that engines fail at any time and some customers can be tricky. But I want to make sure that the place i select don't use bad or cheap parts pretending they are good quality OEM or that will not respond well to any issues I may have with it after the fitting is complete. Not looking for cheapest, looking for place of mind. So far I have been referred to NWS in Shropshire but waiting time is 3 months. Any suggestions are welcome, especially if you have used them for an engine recon and had a good experience. Have a great day! Mark