Having had control over a few, and also produced a definitive paper on the subject way back, I can confirm that foamed runways provided a largely psychological boost rather than any practical value. There was never any evidence produced that foaming or not foaming made any difference whatsoever, and the USAF once produced a study which confirmed that fact.
It could also only be completed at those airfields that were provided with the purpose built equipment which was towed down the runway. If all you had was your standard crash/fire vehicles, it wasn't really practicable because they were designed to produce a lot of foam in a hurry, but not over any length of time, and replenishment between discharge meant that the foam path would take too long to lay and would be breaking down at the start point before you finished it. Those vehicles also could not produce foam while moving, [always a huge disadvantage], so they would have to be towed by another vehicle. Meanwhile, there would be the problem of the aircraft itself having to circle for an additional hour or so...
XA 929 and XH163 were both Cottesmore based at the time they were lost, in the same week.