UK based toy makers with animal-like sex toys:
Also Neotori (Germany) and NaughtyFoxToys (Germany) should reach you fairly quickly. There is also KnotMeToys (Poland) and FeralizedToys (Sweden) that shouldn't take long either.
From the U.S. it will take longer to rech you but I mean if all your worried about is if they deliver or not then there is:
And of course DirtyInternetToys/AmericanMeat.
I second john thomas toys. Not uk based but I know they are. Their toys were pretty cheap for the sizes I got. My only problem was their butt plugs weren't my favorite. The bottom where it is supposed to sit is only an inch or 2 smaller in circumference and would be awkward to have in for a long time
Sinnovator are my favourite and have never disappointed, the texture of the toys excites me to no end and while the shapes look a little unrealistic, they're the most pleasurable I've found. My favourite is their extra large hellhound which always makes me cum before I reach the base of the knot, but does take about half an hour of stretching to get there.
John Thomas are great value if you catch them doing a sale (like right now), but from the designs you can tell they're designed for women. I have a diablo's finger from them which works amazing anally, but it's not really a traditional animal dildo. The knot toys look terrible in my opinion, they aren't traditional knots because they're designed to be vaginal and are more like half a knot.
Whatever you go for, X-Lube is perfect for getting knots in without too much friction. K-Lube and J-lube are also good, but X lube tends to be easier to find and lasts a lot longer.
Not dildo related but I've got a pair of Mason's hindpaws from weredog (UK based too), which is a pair of silicone dragon feet, if you're into that sort of thing. They're clumsy and need a lot of lube to feel good on your dick, but my god when you hit the sweet spot it's one of the most pleasurable feelings ever, it had me tensing up my whole body.