I have tried a number of methods in the past - including this sort of tight area launch. The only way is to load the tip. I have tried plastic bags, canvas bags but the best weight which slides off easiest (which is what you want in this situ!) is dry sand - works without having to fold tip as long as you have hybrid or bow.
So, get a bag full of dry sand (where you are or from the nearest dry beach) and empty sand from bag onto the kite. Usual self launch.
As it is a grass area the sand will still be there to put back into your bag! But then what about self land? hmmmm, maybe need two bags.
Word of warning - I also tried the attach leash to bag methos - fine in constant light winds, but gusty??no way!
I even onve tried a release mechanism which was attached to the LE and then to an anchor.....needless to say I abandoned that one!