It has now been 6 weeks since my treatment and overall I'm okay with the result.
Joseph was very polite and helpful and explained the process in detail before we started. The prices on Treatwell need to be updated though as I was charged £35 on top of the quoted price due to my hair length (shoulder length).
The treatment gets overpowering at times during the blow dry stage. I was given a towel to bury my face into while Joseph was using a mask, as the product tends to fly everywhere.
The most important thing to be noted here is that this is a traditional treatment - you are reminded not to tie your hair or let any water on it for at least 48 hours. This fact is not communicated properly on the website.
Anyway, the overall effect after the first wash was great! My natural hair is frizzy and curly and after the treatment it became soft and wavy.
Unfortunately, the effect began to disappear after around 4 weeks and now most of my hair has returned to its original state. I've been having this sort of treatment at other places since 2013 and it has usually lasted for 3months on average in my experience, every time. So, I was a bit disappointed by how soon the effect tapered off this time. The cost-benefit ratio for me was not favourable on this occasion, therefore despite the great service I received I don't see myself getting this treatment at this salon again.