Alcohol has always been heavily taxed but you have always been able to buy 40 pint home brew beer kits, or even home distillation jobbies and flavours of whisky, rum, gin etc.
Theoretically you should be able to continue to buy flavour concentrates. What concerns me is if they have to be distanced from vape product and cannot mention suitable for vaping - or even worse have to state not suitable for vaping on the packaging to avoidbeing taxed as vape product how would any newbie DIYer know which are safe to inhale and which could contain oils which are good to eat but dangerous to inhale. I can buy a shitload of food flavourings from Tesco, but I'd not be confident enough to vape them.
I know I'm going a bit off topic here, but you know some people are bound to try it.