Bad vehicle service, what to do ?

[Maîneÿ . . .]

Ask the guy at DAYCO to put something in writing to you stating that the tensioner should always be replaced along with the belt (industry best practice), and that the tensioner was a part commonly available. 

Ask the guys at Repco to put something in writing in regards to their assessment of the damage and probable cause, noting the chipped tooth and leaking seals.

With this information attached, along with the bill from Repco I would write a letter to the manager of the dealership who had done the faulty work. 

Be specific, but professional and acknowledge their gesture to pay some of the repair bill. 

Stipulate why you feel the dealership are at fault, highlighting the comments from DAYCO and Repco, then state the $ amount you feel they are obliged to reimburse you. 

Give them 7 days to respond to your request, after which time you will pass the matter to your legal representatives if they don't bother to respond, or their response is not to your satisfaction.

Sometimes in needs to be put in writing with the facts and argument plainly stated.  It also needs to lob on the desk of the right person too in their business.  Whatever their response is will determine whether you need to take it further.

X 2

Get the MIL involved on a professional level and give her full controll to act on your behalf as your legal council

you continue with the big lap and forget about it while she does the work she has studdied for for many years 

[Bird]

The Honda techs said its bollox too and they are only protecting their dealer network......

Play the poor wrinkly old retired broke person, who has had to start work cause the angry thieving scum dealer ripped you off.....

http://au.news.yahoo.com/today-tonight/contactus/suggest-a-story

[heath74]

I'd go in the middle ground, from what I gather you are chasing 1500 total? I'd tell them that you appreciate the offer of 500 to make good, it that you are actually up for much more, and that unless you can get 1000 you will be taking either legal action.
I'd do it in writing, and I'd include a list, but not copies of, all documents you have kept.
If they say ok call it a win and move on.  If they say no or offer 750 for example, you can make a call as to accept or not.

Understand why you don't really want to get MIL involved.  After that I'd get on and enjoy my trip!