Do we know what these were?
Presumably the four in 2010 related to the SMILE trial, which, given it was looking at the Lightening Process, a form of NLP, a profoundly controversial approach, as a treatment for ME/CFS in children, is hardly surprising. As argued in the forums here, an insistence on children lying about their medical symptoms and ignoring any negative consequences is tantamount to child abuse.
The next did not appear until some six years later when the FITNET trial was announced in 2016. Had Crawley already established her narrative of being the victim of anti-Science persecution, including vexatious FOI requests by then, certainly it was already a well established narrative of the PACE researchers well before then, though at their FIO tribunal the judge dismissed their claims of harassment as amounting to no more than someone having been once heckled at a conference?
Presumably Crawley in her talks and press releases does not specify which of the FOI requests in relation to her own work she considers in particular to be vexatious. The recent surge in FOI requests this year presumably also includes those concerned that Prof Crawley is being less than accurate in her accusations of harassment in her talks and in her PR about her work. This would include the Tymes Trust's request on levels of reported staff harassment (zero) and this FOI request, as well as that by David Tuller addressing the concerns about the ethical approval of her earlier 'service evaluation' assessing the level of previously undiagnosed CFS in non school attenders.
Does Crawley contend that the FOIs in relation to herself were vexatious in relation to their content or simply because they were made? Certainly those that I know of raise concerns that Crawley has been less than accurate in her contentions, suggesting that they were addressing valid concerns. If that is the case in all, then though Crawley may be vexed at being 'found out', 'vexatious' is not a fair characterisation of the motive for these requests which would be demonstrably in the public interest.
