It was not Lambourn 'one' we had 3 there off the top of my head.
I honestly don't see what your issue is... You picked the dates, or the farmer or whoever... and it was your call to agree to it, change the site and so on...... if it was a mistake then such is life, we all make them from time to time. You are the event organiser of your event, so organise it as you see fit.
I get the clash is not ideal for you but worth remembering that it was not my doing', I have considered the impact on the PMC members and come up with the above solution after speaking with a good few of them. I have had great feedback from them who seem to agree that it's a suitable and fair option. ( we could just not bother with the second event if you would prefer? )
I think you need to relax.
SW
until