Don't go down the cheap road Thomas. Source the best quality products you can get. The amount of chemical needed for an average days work is small, a few pounds worth at most, what are you saving by buying cheap, a few pennies. for poorly formulated products that can cost you more in the long run with damaged pumps etc.
I have never used Ashbys products so I cannot comment but over the years I have used Extracta, Alltec. Prochem, Solutions etc always buying top grade and moving on if I found a better product.
Buy Quality Thomas, every time and the end result will always be better.