@whitevxA lot of the brands discussed are not available in bricks and mortar stores in the UK either, we have to order online or from specialist detailing suppliers. I use stuff from all over the world: Chemical Guys, Poor Boys and Collinite are American, Koch Chemie and Scholl are German, from Britain I have Meguiars, Autoglym, Dodo Juice, GTechniq, Autofinesse and CarPro.
In terms of products it all depends how deep down the rabbit hole you want to go! Polish, protect and shine really needs two products for best results. I assume you are applying by hand, so my recommendation would be an All in One (AIO):
Autoglym's Super Resin Polish. This isn't an abrasive polish, more of a "glaze" meaning it fills fine marks to achieve a smooth finish and shine enhancement, rather than removing a thin layer of top coat paint. It easily achieves nice results by hand although after a few months the fillers will wash out and it will need treating again, if you want it to last longer top with a durable sealant or wax and you'll probably see 6 months longevity from it.
Shake well before use, apply 3 skittle sized blobs on a firm foam pad and then work in small circles over an area about the size of half a door. Wait until dry to a haze, buff off the residue with a quality microfibre (not the crap they sell in supermarkets on the cheap, something like 350+ gsm Korean edgeless plush microfibre). If it gets a bit dusty coming off then dampen with a fine water mist. And don't get it on plastic trim or rubber as it's a pig to get out!
Autofinesse Tripple is worth looking into too, it's a similar product AG SRP and some prefer it but could be harder to obtain down under.
Autobrite Cherry Glaze is magic stuff, smells lovely(!), fills excellently and gives everything a warm glow but the longevity is rubbish, it lasts about a month outdoors if you don't top it with something. Probably an online order job in Aus too.
If you prefer permanent correction of minor defects and are willing to put in the elbow grease, Gtechniq Nano P1 is one of the most effective by hand but it's long, slow and hard work. There's no protection layer at all with this as it's purely fine abrasives, so you must top it with something. When cutting to correct you'll want a good firm foam pad, otherwise all the rubbing is for naught.
If you're happy to do a two stage process there's loads of easy "spray on, wipe off" waxes and sealants that can give a few months protection and a bit of shine but they're not going to hide any scratches so you would need one of the above polishes first. Think of this as an optional second step to make your work last longer:
TAC Moonlight, Gtechniq C2v3, Gyeon Wet Coat or Kamikaze Overcoat are all hardy examples of the spray ceramic breed
Very easy to apply, generally misiting a couple of sprays onto a panel, spread around with one microfibre and remove excess with a second microfibre almost immediately; some are recommended to go onto a car that is damp after washing or be rinsed off immediately so do check the instructions. Waxes, sealants etc generally don't bond well to SiO2 coatings, so don't waste your time topping these with anything other than top-up sprays of the same chemical after a few washes.
Collinite 845 is a hybrid liquid wax that I've sworn by for years, it lasts 3-6 months and leaves a lovely waxy glow on darker colours.
It's more work to apply then the spray stuff as it has to be wiped on with soft foam then buffed off after a quick cure and I do two coats. If using ensure you warm the bottle first and shake very well, then 4 penny size blobs is enough to do a whole door, you want it on really thin otherwise it's awkward to remove later.
Whatever you polish with, ensure the car is as clean as possible first because you're going to be rubbing all it all over and don't want to be dragging dirt across and creating scratches. One of the biggest things you can do to protect your car's finish is wash it carefully: that means spraying an All Purpose Cleaner (APC) on the lower areas to loosen as much dirt as possible, pressure washing thoroughly, then using a well lubricated shampoo with a deep pile or chenille noodle washmitt. Under no circumstances should a sponge go near your paint! And for drying afterwards, you will want a big plush microfibre, no old bath towels or chamois leathers! Poor wash technique imparts many fine scratches (swirls) that really dull the finish shine over time.