Remember price of O2.5 goals at 7am and if drifted at 5 mins lay the selection

I'm trying to incorporate the following into a trigger that remembers the back price of the the over 2.5 goals market at 7am for matches that I have selected and if the price has drifted by at least 1 tick at 5 mins prior to kick-off, to then proceed with the remainder of the strategy, which in my instance is to lay it in the 0ver 0.5 First Half Goals market. Sounds simple enough but I am struggling to implement this. 

Any help appreciated. 

Thanks