Not just WoF, but virtually all magzines and books have some sort of bias to them. The trick is to not limit yourself to one source, and piece together the commonalities between them to get the general idea. I have copies of articles dating from the TSR2's introduction up to the present, so naturally there is bound to be some imformation that doesn't match the rest. WoF is good, but it's not the only thing.
Even if the Ministry (by the way, are we talking about British or Canadian?) found it unsuitable, it was still considered. The WoF article never stated that an order was set in stone. There have been plenty of 'investigations' for aircraft in roles that don't seem to fit the primary mission. It all depends on the parameters set by the customer. A fighter for one nation could be used as a bomber for another nation and visa-versa. The Arrow fighter was bigger and more powerful than the Mirage IV bomber, hence reflecting the requirements set by the respected countries. An example of this point. They could easily switch roles and still perform, namely an Arrow bomber for France and a Mirage IV fighter for Canada. Given the exceptional performance of the Lightning and the the fact the the prototype TSR2 matched, and in a few cases exceeded it, a drop in such a performance level would still provide enough to be highly effective. One only has to study the just how much each country had to protect. Unsuitable as an interceptor for the UK, but attractive for Canada. Britian looked at the Arrow as a fighter, but some found it to be too big. So, instead, they looked into buying it for GOR339.
Another area to look at for an example of this is North American Aviation. Namely the A-5. A nuclear strike bomber for the Navy. But, NAA submitted it to the Air Force as an interceptor, with a couple of different versions to choose from. Not produced, but still considered. Which is the main point.
Just because the role may seem out of place, was never built, and only one writer chooses to mention it doesn't mean it should be ruled out completely as being farfetched and 'bias'. Even if it was at an early design stage. Exactly when was it ruled out? Can we be sure the idea died at the conference, or was some time later? How do we know the th idea was not carried over into the final model? Vickers was still the prime contractor, so why not run with it? The more sales, the better, regardless of what it is used for. This was post 1957 Britian and the aviation industry needed to sell anything it could.
The author still has the clear advantage of actually being at this conference, so it's still our word against his, reagardless of any claims of 'bias'.
And one thing I've noticed is that, yes, the dedicated multi-role aircraft is a nightmare to bring to reality. More successful have been single role aircraft that are adapted for other roles. Otherwise, there would be no StrikeEagle, no BombCat, and no Prowler. All of these aircraft took on role they were not designed for and, in the case of the F-15 and the F-14, many refused to even consider it (the 'Not A Pound For Air-To-Ground!' slogan). Yet when the new roles were applied, they found they were very capable, extending their usefulness considerablely. So, proposing a dedicated strike aircraft as a fighter doen't seem all that much of a stretch. Or even opposite. But it is just a proposal.