It is reported on a Yahoo Southend Airport forum that the Captain of the 'shakedown' flight passed the request for adjustment of the trim tabs to the Easyjet engineering rep at Southend and that he wrote out the request for adjustments to be made by the sub-contracted MRO. This report states that he misunderstood the sense in which the actuator rods needed adjustment and that the MRO did, in fact, carry out the work as requested unaware that the out of trim was the reverse of what they hade been told.
I cannot vouch for the veracity of this report in any way, I'm merely passing on what is being said on that website.