For which turbo?

It sounds to me that the piston is somewhat seized and the cable is stiff.  As recommended you can free the cable with light lube from the top, working it in and out as you go.  Replacing cables is a big job, as you have to lower the tank.  If you do decide to replace, OEM is highly recommended.  Some of the aftermarket ones just don't fit properly.

Rebuild kits for the calipers are available and inexpensive if you want to have a go yourself.  If not, decent aftermarket calipers are also plentiful and quite inexpensive.  If you go that route, I'd recommend doing both sides.

Get some good silicon based grease (such as 'Ceratec') to lubricate the sliders after you've cleaned them up.

There's loads of info on brakes in our 'how to' section.

Sorry. I've just realised that the second pic is from your Celica! D'oh!

To do list:
Sort out bend of charge coolant pipe where it gets thin.
Source new 10psi wastegate actuator
Rework wastegate hose to go direct to turbo
Remove old o2 sensor (x3) wiring and replace with bungs
Refit under trays
Get it through an mot
Work on oil drain leak.. more.
Return current ecu for new one in 2 weeks time.
Buy new tyres (AD08)
Enjoy it

So.. following my foray into 25 psi wastegate actuators masquerading as 12psi ones. I find myself in need of a decent 10psi actuator. It needs to have the dog leg for the arm and be as long as possible.
Does anyone have any recommendations?

Not just you.

Thankfully, as reported in the associated thread. Manky.  It seems to be limited to the top end.

Very shinny!

Is it just me or does anyone else think there's a fair amount of sludge under that cam cover?

Cleaned, polished, waxed & roof treated tonight - ready for some summer fun.

Cable wise, with them disconnected see if you can push-pull.  The rubbers disintegrate & let in water/dirt.  If they move at all they can be freed with a very thin oil down from the inside, but it's a very slow process.
Search 'Venhill' for a recent thread about the rubbers.