It's not like any Ariel I've seen. The little curved tubes that the rear brakes mount to resemble those of a Koga Miyata Ridge Runner. Pretty cool how they match the wheel radius.
I just checked my massive e-stay images library, and the closest I've found is this one:
https://www.bukalapak.com/products/8yhf ... e_mobile=1
It has the number 483 on the seat tube. Never saw or heard of one anywhere else.
The major difference I can see is that the Merk has no head tube gussets. I can't tell from the pic of that white bike if it also has the little horizontal tube behind the seat tube that connects the chainstays, much like the little tube you'd see on an Alien ACX.
It also appears that the Merk is one size smaller than the white bike. No front mech on the white one, and the rear mech cable is not there. Looks as if the brake cable routing is the same, although it's hard to tell from the pics.
In any case, I'd say they're both uncommon, and they look to be steel, but I suspect that Merk is high tensile steel, otherwise the seller would have probably mentioned it if it were 4130 CroMo.
Can anyone tell from the pic if the rust near the rear droputs looks like it's made of cheap metal? It looks darker than any rust on any of the bikes I've seen.