Mate I am gutted, It sounds like you arent pumping the LE up enough for one and 2 the kite will fall out of the sky if you let out the bar lots when its above you. Remember flying it on the beach at Camber in all be it light wind. We didnt have it sheeted at all, In higher wind (30kt), the kite can handle it, especially as your a bit more Pie hungry than me, but you need to watch how much and how fast you sheet it (remember looking at that knobber on the Slingshot Link! Remember the bubble forming near the LE on the top edge,) well that happens when your sheeting the kite, sheet too much and it will try and invert! But only in mega high and gusty wind!
As far as the stopper goes, I used to reach forward and give it an extra tug to make it stick and never really let go of the bar that often, must be weird going from your C’s to the Ones, trust me mate it will click into place. How are you finding them apart from that?
I kited on sat and then watched with Em on sunday, My mate crashed his new, 07 Waroo directly down and the thing literally split in half down the middle just leaving the LE, that wouldnt happen with your one dude! Its just learning to fly it without over sheeting out!
Wish the wind was better that weekend, should have spent more time flying them on the beach.
Call me if you need to chat about anything mate