I happen to disagree about Halfords stuff, they sell some good, really underrated products. For example, AG SRP and EGP are great, especially considering they're off the shelf products, and they are often overlooked or avoided as they're available from Halfords. Likewise, Halfords sells Zymol Natural Car Wash which I really rate and Megs Nxt Generation Speed Detailer is pretty good too. I have found Halfords own brand Intensive Glass Cutter to be good, as have many others, although it doesn't beat Cerium Oxide for removing rain repellent etc, even when CO is applied with a MF - infact Cerium Oxide is the only thing I've found that will remove some repellents. You can even pick up a pretty good mitt and drying towels there.
Overall Halfords has less choice than any online detailing shop and may even be slightly more expensive but I certainly don't think it needs to be avoided.
.... and this is coming from someone who really doesn't like Halfords!
AG SRP and EGP might be ok... but users tend to use far too much SRP and end up with a very powdery result. SRP also contains a lot of fillers.
I can't comment on the Zymol car wash as I have never used it but £7 for 500ml is very expensive, same goes for the Megs SD.
Halfords does have much less choice than online detailing shops and is more expensive than online... its ok for an emergency sunday afternoon and that is it imo.
We're talking about quality of finish here and you won't achieve that just from products bought at Halfrauds.
I agree people tent to use too much SRP but that doesn't make it a bad product. SRP works as intended, it contains lots of fillers as you say which mask swirls and ultimately provide a better finish. It is also very, very, very slightly abrasive so will remove some light scratches and marks. As for Zymol car wash being expensive, it's no more expensive than Chemical Guys and it's actually cheaper than Dodo Juice and some others. Maybe expensive if you're cleaning several cars a day on the cheap but for your own car, it would last a long time, and it's convenient as you can pick some up if you happen to run out like I did recently. Don't forget p&p when buying online.
So in summary I totally disagree when say that you can't achieve a high quality of finish with products bought from Halfords alone. Don't get me wrong I have bought many products not available from Halfords, but I would still be very happy only using products for sale there. Zymol, AG, Megs and so on.
I think a lot of the detailing products are a waste of time anyway, e.g. snow foam. I foamed my last car for 2 years, then got bored and sold the lance and remaining foam, after all the a pH balanced foam won't remove anything a quick pressure wash won't anyway. People will disagree but thinking logically - if a pressure wash won't remove some dirt, then foam dripping off the car won't either. B0llocks to all this "dwell time" to let it soak. Get a mitt on there, 2bm and get it off