I think different subjects have different types of workload.
The children don't do MORE work in an English lesson, than a maths lesson, they do the same amount, but the format is different.
English teachers don't ever have to get their calculators out and check the maths behind EVERY SINGLE CHARACTER ON THE PAGE! - which can happen in maths, so half a page marked like that can take longer than 20 pages of sentences! ( particularly when the whole class will have done different calculations)
In science, we do risk assessments, requisitions and practical try outs, not necessarily for every lesson, but for more than half of them. You have to retry most practicals most of the time, for example, doing a hydrogen peroxide and celery lesson toady, had to check what results the class should expect, so I could plan their results table for them. Last week's results table no good, as it has to be specific to THIS batch of hydrogen peroxide, and THIS exact level of freshness of celery.
A lot of planning of science lessons is quite complicated, actually, and we spend a lot of time discussing, requesting, negotiating, brainstorming, compromising etc with technicians. And we can't always have what we thought we were getting, so replanning features quite heavily in the workload too, for example told yesterday no calcium carbonate powder was left for today, so had to plan completely different iron extraction practical overnight....
In science we have to keep up to date with the constantly changing and evolving subject, particularly for courses such as BTEC, where last years understanding, of Saturn, for example, is simply not good enough for this year's assignments. I don't think discussions on the issues found in Mcbeth are going to evolve as fast as discussions on sellafield, etc.
There are a lot of "hidden extras" in the workload of a science teacher, and I'm sure there are for other subjects too. We have astronomy units that can only be taught before or after school, for example, as they need darkness, and other things.
We have a lot of maths based work, and a lot of literacy based work, and personally I find the maths based work easier to mark, but not everyone does.