mrfixer

Possibly piston slap.

On a Yaris its likely to be the front ARB bushes.

A 2013 Auris is almost certainly R134a. I wouldn't bother going to a Toyota dealer. Try to find a local aircon specialist who is working on these day in, day out.

Those are anti-rattle clips. You can buy then as a brake fitting kit (try Mintex). To stop squeal try smearing Ceratex brake grease on the back of the pads.

Get a four wheel alignment done at an alignment centre (NOT Kwik Fit or Toyota). Expect to pay anything from £40 to 100. Get a printout of the before and after settings. It will quickly reveal any suspension or chassis damage. Note that in the UK cars will often drift to the left slightly due to road camber.

Look for a local Automotive Locksmith. They will be able to programme it.

Yes. Toyotas have fast idle on cold start. Should drop back to less than 900rpm after a few minutes.

Please post up your emissions test results.

The U340/341/E was a popular transmission used on Avensis, Corolla, Celica etc. It is easy to obtain parts for rebuild - a complete seal/rebuild kit is about £200. You need someone with experience to do the work. With a high-mileage 2005 car it is probably better to fit a secondhand gearbox.

For C50 transmission its a 75W85 or 75W90 to GL4 or GL4 & 5

This can be due to 'cupping' of the treads - an uneven wear pattern that generates a humming noise. Ideally you should rotate the tyres every 5000 miles or so to even out the wear.

GL-5 LS means that the oil has friction modifier additives for limited slip differentials. Your Avensis does not have a limited slip differential. I doubt using it would cause any damage but possibly the gearbox synchro would not perform optimally.

Most Toyota manual gearboxes take a GL-4. What is the engine series code on your car?

Personally I would put a 75W-80 in there. You'll get much smoother low temperature shifts and less baulking on downchanges. Make sure its a GL-4 oil and NOT a GL-5.

Either a coolant leak somewhere or head gasket problem. Best bet it to take it to a garage and ask them to pressure test the cooling system.