ok well i think ive come up with the solution for the cover relase set ,ive come up with the idea of using barrel locks as the pulling mechanisum,now these are going to be fitted some where underneath the quaters,and are worked with keys ,so you cant see them but can get to them if you realy have to get the tarp open.......
so off to bunnings and came back with viarous bits and pieces to try and create the idea heres a very ruff sketch of the idea......

ok so there we have a cable running thru a tube,the cable is connected to the latch at one end and the other a barrel lock,
the idea being is you put the key in,turn it and it pulls down on the cable and realeases the cover latch..........
now im going to atempt to turn that into a working set up!!!!!!!
so hopefull if all goes well it should be done by the end of the week ,fingers crossed it all works out!!!!!!! will get pics and explain as i go along,but the idea is simple and should work well
remeber that this is only going to be a emergncy set up as im using a full central locking type set up for the 90% of the time to be used............