I have now noticed the rear passenger side brake makes a chugga chugga chugga noise when I brake to slow down

Only seems to happen maybe when they are hot. Because you won't get that noise during the early part of a drive.

I know it is brake related because the noise can be recreated if I pull the handbrake whilst the car is still moving

Now I have just inspected the brakes thru the wheel and the discs look fine, and no obvious burning marks either

The pads look very healthy too

I fitted them myself over a year ago and I believe they are ate brand from euro car parts

They have prob done 10 to 20k max

What is this noise? I've ruled out tyre noise as it seems to only happen when hot

I will take the wheel off to inspect closely. But I would like to hear what you guys think it is

Remotely possible warped disc?

Rusty rear discs always a possibility as very prone due to lack of use, owing to front brakes doing the major braking.

Definitely you need to have a good look see in that area.

sounds like a seized caliper so its heating the disc up whilst driving. When you then brake its overheating the disc and making the noise. Get the caliper off, cleaned up and greased and see what happens, if it still does it either a seal kit to renew the caliper or reconned caliper is what you need.

Mine is an Octivia and the front brakes make that rumbling noise. couldn't figure out yet. Pls help.

sounds like a seized caliper so its heating the disc up whilst driving. When you then brake its overheating the disc and making the noise. Get the caliper off, cleaned up and greased and see what happens, if it still does it either a seal kit to renew the caliper or reconned caliper is what you need.

Does sound like a viable cause to the problem

In terms of removing and cleaning,

what exactly will I be cleaning though?

From my memory the pads sit on a runner, so wire brush the rust off making sure it's all smooth and clean, and re-apply copper slip

In terms of the caliper pins, from my memory they are sealed inside rubber boots and shouldn't need worrying about.

Is the above correct, and what else do i need?

It's usually the piston in the calipers that needs a new seal but I've come across issues with the sliders bieng caked up before.

This has happened to me countless times... it always goes away and might not happen again for weeks or months.

It may well be a sticking piston but also have a look at the handbrake mechanism, the operating lever on the back of the caliper tends to stick as there are no handbrake release springs. There is a sticky thread at the top of this forum telling you all about it.