Tuggles and Toddles shared the same body colour, but had different poses and hair colours.

There are a bunch of anomalies with this set release, because they can be found Mint in Box with various colours of seesaw. Pink/yellow, aqua/pink and yellow/aqua are all possible accessories for this release. This is based on American boxed ponies, but from the promotional material in the UK, it seems likely that the same anomalies existed here. The UK insert showed them with yellow and pink seesaw, while the comic image (below) shows pink and aqua. French boxed versions have been found with yellow and aqua, like my boxed American one, shown below.

Although I never had this set from new, when my sister and I found them at a carboot sale, they were with a yellow and pink seesaw, which could only have belonged to them - but in the absence of UK Mint in Box twinsets, we can only presume that all three accessory variations were possible for this set in the UK as well.

I have owned two boxed sets of this twinset from the US over the years, and they each had different see-saw colours. It seems a very common variation, and one which also affects the other twinset with see-saw, Puddles and Peeks, who can also be found with multiple seesaw colour variations.
Although tbe back of the box is different from the North American release, the front appears to have been very similar in the UK - just with the names altered. The UK release would also have had a blue snugfit box rather than the yellow American diaper box in the below image.

Tuggles & Toddles's Characters

Tuggles and Toddles's UK backcard story was more or less the same as that in the North American release, albeit with the names changed and some words amended for local vocabulary (mother for Mama for example). The story details them having fun at the park on the merry-go-round.
They also appeared in the comic, and not always with adult supervision. In one story they were playing see-saw in the snow, when Toddles fell off and found a lost bell. They head off in the snow - alone - to find out if any of the local cows have lost their bell. This leads them on an adventure to meet Butterball the yellow cow. Her magic bell was a key to an enchanted meadow, where fairies harvested buttercup essence for Butter Kiss to use in her sundaes. All of that from a fall from the see-saw.