I have experience cleaning around eight pairs of glossy Hunter boots and I purchased this kit as several were particularly badly affected with blooming and needed cleaning every two or three days which made them unsellable.
The oil based cleaner works quite well to restore the shine of the boots and it goes quite a long way, unfortunately the silicon impregnated sponge doesn't do a very good job of sealing the surface, neither does it contain much silicon so it's soon gone. A real shame Hunter couldn't get it right, the kit only kept them nice for a week at best. Fortunately I found a German manufacturer [...] who specialise in rubber care and their kit virtually eliminated the blooming on my boots. Although comparable in price the international post makes it initially unattractive, but it's cost effective as one rubber doctor treatment lasts for months on my personal pairs!
I would therefore suggest to buy the Hunter kit from Amazon only if your blooming is not too severe, but definitely make sure you get a treatment of some description. If you neglect them they will dry out, crack and leak. Neither try olive oil because of the acidity and NEVER try nail varnish remover which is another Internet suggestion. Car tyre shine is indistinguishable from Hunter's buffing oil, except it will swell the rubber visibly in minutes so don't be tempted to use this either. I very nearly wrecked one pair of boots trying to save money so save it for the wheels.
Because the boot buffer is available separately for half the kit's price, this could be another way to go as the silicon sponge is so pathetic and I was disappointed the buffing cloth was just an ordinary duster (with Hunter logo) rather than a micro fibre cloth.
Edit: I found a better alternative that's under a fiver and works just as well as Rubber Doctor plus you get 250ml's so no need to skimp! Try a Google search for 'Fairfields Boot Buffer' from LRleisure as these guys really know how to care for your rubber.