Thanks for that info Roland, it is great to hear about these things first hand! I had the honour of knowing several WW2 pilots and aircrew and it was often a very different story they told, from the history books.
Interestingly and coincidently (and a bit off topic!), one chap (my boss at the time!) was a Seafire pilot (he scored first ever kill in a Seafire and his only victory, during Operation Torch) and also an observer who flew in the 'Wedding-ring Wellingtons', also attempting to clear mines! As you said, if they flew high, it did not work and lower, any mine would explode under the tail and tip the nose down....no fun when you are at 50ft already!