That's a very big "if"! It's only with the benefit of hindsight that you can say it was an "unfavourable" contract from the borrower's perspective.
Frankly, this story just doesn't add up.
Why would the broker amend the form without the applicant's approval? There was absolutely nothing in it for him.
To be honest, I really don't buy the "I don't know what a tracker is" line. .
I'm one of those that didn't realise what a tracker was as I was getting a mortgage in that time period. I was just used to fixed and variable so I stuck with what I knew.
I agree with you the story doesn't add up. Why would you many years later suspect the broker of skullduggery. There is no reason for the broker to amend the form unless the tracker was no longer available. The OP knew he was being offered only a variable or a fixed rate and was happy to take it.