So in case anyone else wants to replace the LCD in their E39/E46 here are a few pointers:
1) You can use any 6.5" Sharp LCD screen but bear in mind there are specific versions for the E39 and E53, the E53 has a different viewing angle so if you get that one you'll need to adjust the viewing angle which is very fiddly as you have a choice of 10 screws to adjust and there's no definitive guide to what each screw does. The one installed in mine by BMW was LQ065T9BR52 but the one I purchased was LQ065T9BR54U. The new one was for an E53 as sitting in your normal driving position the screen was washed out. Ordering the right LCD first time will save a lot of hassle but you can adjust an E53 screen to work in the E39 as my photo shows.
2) This is quite doable for anyone used to taking things apart as it's just a case of following instructions but the electrical plugs and ribbon cables can be a bit testing to remove and re-install. As with everything on the car they are 15+ years old so anything can break if you're not careful.
Overall I'm pleased with the outcome as the new screen is brighter than the old one after adjusting it so although it still re-sets to 50% brightness after turning off the ignition it seems to be bright enough at 50% now.
Here are a couple of photos:
You can see some light scratches and a small area top left where the anti-glare had been damaged on the old screen but in reality they weren't really noticeable until I got the new screen
The new screen is definitely brighter than my old one at 50% brightness but I think that adjusting the image using the screws on the rear made a difference as one of them was a contrast setting
Here are a couple of links to 2 DIYs as well in other forums but never really sure if this is allowed or not:
LCD replacement: https://www.bimmerforums.com/forum/show ... een-Repair
LCD adjustment: http://www.bimmerboard.com/forums/posts/211409
