Gen 3 automatic box oil change

One of my two local suzuki dealers quoted 350 quid a couple of years ago.

good god

I'd pay that if I thought they would actually do a full flush.  But I expect they drain out whatever comes - probably a litre or two only - change the filter if you insist on having the old one back as evidence, and top it back up.

I have the same suspicion.  Rare is the dealer tech who will do a job thoroughly when doing it half-*rsed is much faster and totally undetectable.

But I think that 350 was what is known in the business as a "go away quote."

That is, when a customer asks you to do a job you really don't want to do (for whatever reason) but you don't want to offend the customer by simply refusing.  So instead you come up with a number that is almost certain to put the customer off.

Either that, or I need to move to the UK and open a car shop.  Just doing transmission flushes perhaps.  

Will do 3 oil changes over 2 weeks running it to work,,then do it again in a couple of years

It could be that, I didn't take them up on it but that was more because I was and still am of the opinion that if it isn't broken I'm not going to start fixing it until it does break.