Hi Pandora,
Others have covered most of the relevant points, may I just raise a couple?
Please don't think I'm having a go at you, because I'm not, but I do think you need to be able to answer them, because they are likely to be some of the first ones asked by the CAA / BA in the event of a formal investigation into a fuel incident.
1) If you thought that the fuel flight plan was illegal (as opposed to just being less than you would have liked to have taken) then why did you go?
I know it's a lot easier said than done, but if you can't see how the final fuel figure was arrived at, and are not sure that it is legally sufficient, don't go.
It's your licence on the line as well, if something goes wrong.
2) What happened about the PAN call hat FCOs required you to make? Only 3 minutes from reserve fuel would appear to make it likely that you may land with less than reserve fuel remaining.
I ask because, if you report someone formally, you must be sure that you have discharged all your licence responsibilities correctly, otherwise you may get dragged into the manure as well.
I'm no suggesting you didn't, just asking!