Two updates. After some admirable persistence we know the following: "Well, I had a long chat yesterday with a charming gentleman from Evans (UK). In summary: Evans do not use OAT inhibitors (including 2-EHA) in their waterless coolants, due to the need for solubility in non-aqueous solvents He was unable to say (for IP and commercial reasons) what inhibitors they did use, but explained that the formulation differed according to the type of engine the coolant was designed for For old engines (with a high brass/copper/iron content) he recommended Vintage Cool, provided that the engine has a coolant pump (that is, not a thermo-siphon design) to cope with the higher viscosity Evans coolants are fully compatible with, and do not harm, silicone hoses, seals etc (claim based on extensive testing)"And Evans' UK website has been completely redesigned. The biggest difference I can find is that the claim for increased engine power seems to have gone. This may be related to the following from the Advertising Standards Authority: After consideration by the ASA of complaints received, the following companies and organisations agreed to amend or withdraw advertising without the need for a formal investigation: Hydra Technologies Ltd t/a Evans Cooling Systems UK 28 January 2015. Jonathan