If the company can't provide a 3rd party test or COA, then you may want to venture elsewhere. But that is totally a personal preference.
I personally am not very fond of a company who thrives off beef protein as its major source because we all know beef is very low in amino acids
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Many companies have been found guilty of protein spiking in the past, so if this is the case I would steer clear unless they have a test to backup their products.
I also don't agree with Labdoor and their rankings because some of their rankings are companies who do not meet label claims
For example, companies who can sell their products under the cost of raw materials should raise a redflag, why it is always cheap, or always on a very large discount or BOGO.
As far as what is available in the UK, hard to really know. Darkhorse has a very good list of products.
PEScience
Core Nutritionals / Merica Labs / Arms Race
Nutrabio
Animal
Metabolic Nutrition
Quest
Ghost
I would also add:
Nutrex
BEAM
Beverly
Rule 1 Proteins
MuscleSport
Sparta Whey
Sinfit
Ryse