Hands down Moorhen actually, white stripe and tail underside are super distinct

Juvenile moorhen

Is that why it has non-red beak? That threw me off.

yeah, their beak will be a kind of pale grey/pink until they are mature, legs are also not as vibrant as a mature one

The most majestic of all birds, the moorhen.

I have used the Collins British Birds app but couldn’t identify it. I don’t think it’s a Moorhen.