That is good news You will probably still be getting the occasional rattle, especially in warm weather but it will surely be less pronounced and much shorter. The filter definitely helps for the most part. What also helps a lot, as odd as it may sound, is keeping oil leakages in check.

Yes, interestingly, I did have quite a leak from bank 1 cam cover after the chain guide marathon despite it being a new gasket and torqued correctly. Some 10mm Stainless washers on the cap nuts cured that leak but not the rattle, but it is pretty dry now bar a very small weep where the cam cover gaskets meet the timing chain cover gaskets on each bank but it is barely a weep. And having replaced the thermostat for an 89 degree stat last year, and subsequently fixing all of my coolant leaks, it is quite a joy to lift the bonnet now. These beasts demand our attention but are a joy once they are right. Thanks again.

I'm glad you've been able to get things sorted for the most part at least. I do have a slight weep from the cam cover gaskets myself but I'll be dealing with thay on my own time and terms. Since I had the water pump replaced properly, I hardly open the bonnet any more. It's getting dusty in there, last time I checked, filling the washer bottle.

Well that was a little short lived. After about 10 days of perfect starts, the start up rattle is back similar to how it was before the filter element change. I have lifted the filter element out again and re-fitted it into the bowl before fitting the cap and it has stopped the rattle again for now. I'm guessing my anti drain valve poppet it worn and moves around a little but I haven't removed it to check yet. I am totally convinced that this is my main cause of the start up rattle as I was already sure it was caused by initial oil starvation so I am happy to replace the filter housing if I can find a new one. But I would just like to be sure that no one on here has ever managed to track down a replacement anti drain valve plastic poppet or even have one made? A good 3D printer boffin could make good money if they could come up with a program or just make and sell them. Fingers crossed for your comments and information.