My LR D4 mudflaps disintegrated on my first trip from Perth to Cape York via Great Central Road and Plenty Hwy etc. As you say it leaves a big hole so I ended up getting Chinese knock offs just to keep it looking good with the Kaymar bar. The Chinese ones have now survived a heap more rough roads than the LR ones with no damage whatsoever and were an easy fit, as good as the originals.
As you say, the only problem is that stones get thrown out the sides, especially with 285 tyres like I have. On my KK they have peppered the 100 series hub covers on the wheels and the electric stairs and also the wood box to a lesser extent. I am going to get extra stone protection for the KK but not change the mudflaps. Even with a Stone Stomper the stones go past it and peppered my camper trailer.
The other issue is that the plastic lower body protection and the Kaymar bar itself are also stone blasted by stones from the front and rear wheels, but I just live with that. 
Can't help with your real question, however. Sorry.
				
			 
			
		 
			
				
			
			
				Bob
2010 D4 3.0TDV6 SE, ediff, LLAMS, 5 x GOE wheels, LT285/60R18 BFG K02's, GOE Compressor Guard, LR Tank, Mitch Hitch, ECB Bull Bar, Kaymar Rear Bar, Traxide, Safari Snorkel.
2019 Discovery 5 SD6 SE, 20 inch wheels, 275/55R20 Nitto Grappler G2 tyres
			
			
		 
	
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