It is the one piece calliper with the four pistons that has the arm on it to mount on the axle. It hasn't been re-sealed for at least 14 years, probably never been done. 

Got a question for ya Hilly.

Thanks for that 408.  Do you happen to know how low it goes when its down and how high it is when its up?

I've got the jack 408 pictured there, bloody handy bit of kit, that's how I get the back wheel off anything that goes on the lift, some bike lifts have a removable section at the rear so you only need to lift the rear wheel a little bit and the remove that section to pull the wheel backwards and down, I was going to mod mine like that but wheels and gravity ain't good for my back so I just use the jack, take the weight, pull axel etc, jack bike until I can lay the wheel over a bit and roll it out, the the back of the lift acts as a little work bench then 😁

I ended up using a couple of car jacks and timber. Probably not the best solution but it works ok and pretty stable. Didn't have to lift it as high as I thought to get the wheel out.

Well fuck a duck aye! Remember the rotor is outa spec as well, fixing the seized piston won't change that, if you successfully recon the caliper you will feel a pulse on the pedal when you apply the brake with that much warp.

Yeah Hilly the disc was fucked but I fitted a brand new one.