I don't know whether XV230 had an 'acceptable' leak the day of that fateful flight, but I would assume it did. Sadly, the 'acceptable' leak turned into something a lot more tragic, hence why so many of us feel the accident was avoidable.
Winco, when you use a handle like yours you provide an air of knowledge and authority that members of the public might take at face value. So, I have to challenge the above quote, because it is plainly speculative and leans towards stating it as a fact.
You have no proof, whatsoever, that the fire was started by an extant acceptable fuel leak. In fact, it is highly unlikely that anyone would accept a known leak in the area of the reported fire.
Winco, your speculation borders on accusing front line personnel of negligence.
By all means, have a pop at RAF engineering policy, but leave the line workers out of this.
To answer Safety Helmut's question about the probe adaptor: yes, it is still used before and after every AAR flight, to check the probe for serviceability. It may also be used a diagnostic tool (with a bowser) for reported leaks in the refuel system.