I've bought all my potting soil from bunnings, and by far the best is debco organic based on current results.
I started off with debco potmate herb and vege mix, then debco organic, and the last lot baileys premium.
I usually use a handful of blood and bone mix, and dynamic lifter/rooster booster pellets when potting up and then leave them alone.
The debco potmate mix went alright, but about 3 months later the plants were showing problems. the fert in the mix had been used up, and the organic stuff I added did not break down, just went moldy, probably due to lack of organisms in the mix that could break down the organic ferts.
Everything in the organic mix has done much better, there was no ferts in the mix and never needed any except for the organic stuff I added.
Everything in the baileys premium has not done as well as either of the debco mixes.
Also, perlite, get some perlite. Way to easy to over water chillies, perlite gives it better drainage and more air to the mix. I've grow chillies before but never did well and I never knew the secrete of perlite until last year. I use about 15% of the pot perlite. If it's going to be wet, aim higher. When I grew some seedlings in august last year, I couldn't keep them out of the frequent rain, only seedlings that did well were the ones in 25% perlite
You mentioned vermiculite, yeah it adds some air to the mix, also it's something to hold some water to stop all that fert you're watering in from just draining away. But it's hell expensive, so I just use coir peat which holds moisture really well also, ~$2 a brick and makes 9L.
I normally put about .75L into each 9L pot I have (I'm using 9L plastic buckets for pots, each pot has 6L potting pix, a cup of blood and bone mix, handful of DL or RB pellets, 1.5L perlite, .75L coir peat, then a few more pellets on the top and covered with the sugar cane mulch)
The potmate herb and veg mix from debco or the baileys might be alright if you are going to use NPK chemical ferts, but for cheaper organic ferts that is simple to use, go for an organic potting mix like debco organic.
