I search the coastal map of where I am holidaying for secluded muddy estuaries and marshes and am usually successful. North Norfolk Coast and harbours.
I do a lot of checking around estuary and wetland areas with Google Earth, then usually a visit to see it in person before I go ahead and play in it. Finding the perfect discrete but accessible spot with water for cleanup still takes a while though. If we get a hot summer and water levels are low, reservoirs can be worth checking out too. Also, it occurs to me that MudBoyAndy on youtube has filmed in some good quarry and gravel pit locations in the Midlands. If you can figure a way to get in touch, maybe he'd have some info.
Just wanted to recommend taking a couple of 2 litre bottles warm water with you and some 2 in 1 shampoo/shower gel. It's amazing how passably clean you can get just with that, especially if you have a friend or small mirror guiding you to any spots you missed. lather up with the gel first before adding any water then rinse off. This will serve you well enough to get back home or to a hotel for a proper shower - as tested many times by me for outdoor wam
Love you, too
