These days motorcycle chain is fairly specialised and usually 'O' ring. Ariels (and all similar) use standard transmission chain. I get Renolds from a local bearing factor. Renolds used to be in 3 grades, I think what we used to see as the 'good quality' Renolds is now the highest grade, I economised and bought middle-grade because frankly the bike isn't going to do the mileage that it used to.
If ordering from chain suppliers don't ask for a half-link, specify a cranked link - a half link is something completely different and not what we're used to seeing in motorcycle applications.
'55 Huntmaster, '56 VH, ' 51 VH, '80 R100RT, '00 Sprint ST (but all those Ariel parts can only make one running bike...)