Product Attributes without Variation Don’t Display

I have quite a number of products on my site – a lot of them have size and/or colour variations. Some of these variations have prices attached, and these work fine. The problem I have is when an attribute doesn’t have a variation i.e. the price doesn’t change. The attributes are not displayed on the frontend product:

https://www.maiseymoo.co.uk/shop/dog-beds/fabric-dog-beds/ultima-dog-bed/

The above product has a size variation which alters the price, but also has a colour attribute which doesn’t affect the price; the size variation displays but the colour options aren’t display.

Similarly the below product has no variations at all, and has a size attribute that doesn’t affect the price, but this attribute is not displayed:

https://www.maiseymoo.co.uk/shop/dog-clothing/jumpers/park-lane-pullover/

Please help!

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