Bonehead, I have been waiting for your response.
The main reason why bonehead that the British did not pick the M1 series is due in large part with a somewhat different concept with the main armor, we thought our version of your design was better, maingun also played into it the decision by a small portion. It was a matter of rifling versus smoothbore. With all the British tankers that I have worked with I have never heard them make the statement that they would rather be cruising around in Leopard tanks.
Having been in the demonstration team on the dorbann training area, where the mobility trails were undertaken in germany, i can tell you without doubt which tank was perfered and discussed, as well as inspected the most. like wise the survey carried out by the ATDU team with each regiment,( this was requested by the director of the school of armour in bovington along side the MOD) the results were leopard first option, while the gun ect may well also have played its part as well as national poltics, but the oveall view at that time was leopard.
The crews liked the mobility, ease of maintenace in the field, cant say other regments but mine was clear. we worked with the local german armour school a lot, the M1 demo team did not provide a very good demonstration, the same occured on the ranges, the gun was not a problem as at the time it was a british gun,.
As for british crews perferance for the M1 in 22 years never heard one, not even in the gulf, personally ive never been overly impressed by the M1 at all every time i see it ,i expect if we had taken leopard it would have had a british gun system anyway at the time. i would still place the leopard over the M1 to this day. if the M1 and challenger were both that good everyone would buy them, as it is, the NATO standard tank is the Leopard. with good reason.