"This is not subnetting is it? Its just 3 seperate networks?"
Depends if you're going by the (very) old classful rules (then yes, they're subnets) or classless rules (then no, they are independent networks, although often still referred to (informally) as a subnet of any larger network address block that might encompass them, e.g. 10.0.0.0/8, /9, /10, etc.)
"Would i be right in saying, this is a Class A address range with a class C subnet mask and should never have been designed this way? Or does it not matter?"
First, as @Jon Marshall notes in his reply a /16 is not a class C; it should be a /24.
Regarding never designed this way - well as Jon also mentions, generally you don't use a /16 as an actual network, generally /24 or smaller, sometimes a bit larger, up to, say, a /20.
Does it matter? That's an "it depends" answer.
Maybe the following, about classful vs. classless, will help . . .
Within classful rules, any 10.x.x.x, that's using more than a /8 would be a subnet.
Also BTW, a /16 or /24 of a 10.x.x.x are never class B or class C addresses, although they would use the same mask.
Classful addresses are determined by specific address blocks. The whole reason for classful addresses, the address, itself, implies the mask to be used. For example, any 10.x.x.x address would be considered using a /8. When you don't use the implicit mask, such as subnetting a classful address, other "rules" come into play (often a bit confusing to those working with classful addressing for the first time [fortunately classful is, for the most part, pretty defunct]).
