at this point i think you did the right thing looks like burning from acidic soil. looks kinda like fertilizer burn lol. i think it just needs time now to recover and the lime to help it out.

Thanks,
The.newer.leaves.are.greener.but.some.are.starting.yellow.specks.
I'll.give.it.a.good.water.and.not.fertilise.for.a.while.

Looks like salt buildup; by any chance are you watering with water from a water softener? If not, best to flush your pot with water to alleviate the salt problem. Could also be burn from applying chemical when the temperature was too high.

Looks like serious burn of some kind to me, as well.

Potash raises pH. Do you know how high the pH is now?

I'd change out the potting mix entirely, as I suspect your potting mix is inappropriate.

Josh

I think this could be due to two things - messing around with the soil pH as well as using a urea-based N product in your fertilizer and causing biuret build up. This is commonly known as 'salt' build up. I would repot with a more neutral potting mix that is well-draining. If you search our forum for either "Gritty Mix" or "511 Mix", you'll find two very excellent container potting mediums that you can make up yourself. Then, switch to a water soluble, non-urea N based fertilizer that has the proper NPK ratio along with all the micronutients. Most container citrus folks on this forum prefer to use DynaGro's Foliage Pro. You may be able to find it online and possibly shipped to Australia. I am in agreement with Josh on this - you may have gone completely the wrong direction, and now have very alkaline soil. 5.5 pH is not too low for citrus. They actually prefer around 6.0 to about 7.0, so 5.5 is still acceptable for citrus.

Patty S.