Hello Andrew,
Yes I did do the a/c test, It was no trouble for me as I had training at ACP Group just last year (C/Guilds and CITB), In the ATA test you have to use a fully automatic machine, de-gas re-gas, show that you know proper procedures including safety and the environment. I use a semi auto machine and gauges for testing, I would say you will need training on AC, I did three days @ ACP, Chris sends you pre course notes to learn and it does help, so the three days can be spent learning more, It does give you a headache all this learning but I think it is worth it, I would say if you work on cars you must like a challenge, so go for it.
Shame about the grease bit, I would be kicking myself on that one but I found the nerves get the better of you sometimes and cause silly mistakes, also using different tools is a bit strange (cant really explain that one).
Thanks for your kind words Frank, yes I think I will have to have a go at master tech, I will give it a little while though, Sorry I missed your talk at Coventry (got held up and didn't keep track of time). Don't think I will get to Harrogate, been taking too many days off and the work has to be done.
Regards, Kim.

PS, good luck Andrew.