It's difficult to really compare without more details - X was paid this much in the last financial year, and that covered these programmes... In the Casualty actor's case, I would guess that that is his only income, whereas others do a variety of presenting and acting jobs, including with other companies, and also advertising jobs, Christmas pantos, Strictly appearances and so on. So if you looked at what he gets per appearance, it might not be as much as others, but it is a good, steady job, working most weeks... It still does seem quite a lot for that, but as I say, difficult to be sure without the fuller details. And we also don't have any context of what other broadcasting companies pay.
Having said that, there is clearly a gender gap, and I care more about that than individuals. Even if it could be explained by a particular presenter doing more hours (which I mostly don't think it can be), then you'd have to ask why women don't get the same opportunities in terms of how much screen time they get.
I agree with the post above that said we should publish all tax returns. I've asked about pay in the past, and been told, "it's a sackable offence to discuss pay." Even if that's no longer true, it's still the culture, and while there is so much secrecy round pay, the gender gap will flourish, which as a general rule, only benefits white men.