Is this the only postgrad physics course of it's kind?

https://www.kcl.ac.uk/study/postgraduate/taught-courses/physics-grad-dip.aspx

It's a physics course for graduates of other sciences. Basically the 3rd year of the BSc, with some 2nd year options if needed.

Can anyone find any other examples of course like this in science, specifically physics?

I've come across another course that was for graduates of any discipline to go into practical astronomy, but it wasn't equivalent to the 3rd year of a BSc, as there was little to no maths/other physics expected as a prerequisite.

Thanks.

Why does it have to include the equivalent of a third year?

I skim-read the link. Why do you think it's "basically the 3rd year of a BSc"? A course that says it's "designed... for physics graduates" would be pointless if it's just a repeat of the last year.

Are you asking out of curiosity or for a reason? If it's for yourself, what are you wanting to do, and what have you done already?

Read it more carefully and you'll see that the course is almost identical to the 3rd year of their BSc.
I don't know why a physics graduate would do this. Maybe they got a low grade but want to go into postgrad anyway.

I already have an undergrad masters in chemistry and I'm looking for courses that allow me to study QM and it's related fields at MSc/PhD level. This course is perfect, but I can't see any others like it anywhere. I detest London, so the same thing in another location would be desirable.

Ok makes sense but what I was getting at is that if you can find a course that is for grads of other sciences that doesn’t necessarily cover the third year of a BSc degree that may also prepare you for a masters in the subject.

Something at that level is necessary though, or you're not going to have a clue what's going on.

I'm in a similarish position, my undergrad was in chemistry but I am going to move over to the squishy science (biology), namely immunology, I applied for and was accepted onto the masters course at Imperial. The first two modules of the course cover the kinda "basics" i guess but since its a masters i assume it'll be at a bit higher level than BSc but should still be comprehend-able, and anyway the self study, huge part of masters, will fill in any gaps. Also because I know I only have like a 1st/2nd year introductory knowledge of the immunology i bought a textbook aimed at undergrads to help me revise and have also sought out tutoring from a PhD student in a research group at UCL. You may want to consider trying similar things to help prep you, i mean its a masters course after all so you'll be expected to do a lot of self study anyhow. So if you do it now then even if the course doesn't start super basic you'll at least be on good footing.