I usually buy all this stuff online anyway, sealants online are a reasonable store. You can buy a repaircare starter kit that has everything you need but it's £100+. Yes you should use the system hardener. Keep an eye on the price at Brewers, they are usually a bit pricey if you don't get big trade discounts from them. Its a great system but price of entry is restrictive, you might just get away with a 2 part filler (Decor fill), if you prep everything well and are prepared to fill and sand a few times then it should do the job, just the risk that the whole repair pops out if you get it wrong.
I usually buy all this stuff online anyway, sealants online are a reasonable store. You can buy a repaircare starter kit that has everything you need but it's £100+. Yes you should use the system hardener. Keep an eye on the price at Brewers, they are usually a bit pricey if you don't get big trade discounts from them. Its a great system but price of entry is restrictive, you might just get away with a 2 part filler (Decor fill), if you prep everything well and are prepared to fill and sand a few times then it should do the job, just the risk that the whole repair pops out if you get it wrong.