I'll never understand why MoD denied knowledge of ESF especially as they part funded the development of it, as well as other methods of fuel tank inerting. Indeed, one of the first aircraft ever fitted with reticulated foam was a Lyneham aircraft decades before the loss.
Why the BoI missed these facts is also one of the XV179 mysteries, but at least the BoI president passed all the (unread?) information to the coroner; he relished reading 40 years of MoD-owned research on a topic that they 'knew nothing about…'.