First off: a cheese for you for a beautiful result!
In the recipe, was there any phase during which the curds were stirred, or otherwise left to ripen after draining but before salting and pressing? There are a number of cheeses (such as the Caerphilly you mentioned, or a Cantal, or even the so-called "stirred-curd cheddar") that are not true cheddars -- they haven't gone through the classic stacking and turning phase known as cheddaring -- but nonetheless are in somewhat of the same flavor family. If you taste one of these on its own, you might say, "cheddar!" ... but then if you taste it next to a real, true cheddar (as in, a really good artisanal cheddar, not the block you can buy in bulk at the grocery store
), you'll see that there is quite a difference. Of course, not having tasted your farmhouse cheese, I don't know how different it might be from a real, true cheddar, but I'm guessing it is more like some of the others I've mentioned.
The unintentional "washing" that you describe -- if it was at the pressing stage when it got drowned, I would think the washing would have minimal effect. I'd say you need to make the cheese again, following the same procedure EXCEPT no drowning, and see if you get the same result. If not, make it one more time, this time WITH the drowning, and see what happens. Who knows, you may have invented a whole new category of cheese!
In any case, it sounds (and looks) like you have a winner ... just wish I could taste it!