Engine oil recommendations

Diesel engines incl Optimal drive - 5w30

does it matter if its fully syn or semi?

Great list :) I used the Castrol website to determine the best oil for my car, 0w30 was recommended I assume this is safe for my 1.4 vvt-i corolla 07 hatch? I've been using this for the last 5yrs replacing the oil every 10thousand k's religiosly 

This might seem a silly question but how do you know that you have a DPF unless you get under the car and have a look (or ring the dealer)?!!  I have no details with the car to show any service history regarding a DPF. I'm concerned that I buy the right 5w30 oil for my 2012 diesel Verso and don't risk wrecking the DPF (if I have one) with the wrong spec oil.

My Avensis 1.8 Valvematic preferred oil is 0w-20, with 5w-30 the next best. 

Every search I make with Opie Olis and Euro Car Parts for example, all come up with 5w-30 grade oils!

I know that 5w-30 is a more common grade, but if the engine is "better" on 0w-20, make it available on the list. 

I think it wouldn’t harm and instead might help the noisy four banger on the rav4 I was thinking maybe I could add some lucas oil aditive to quiet it down a bit on startup, after warming it is not as loud.