I once landed an R-22 in my backyard during training, so I think a Lilli would fit.
Times change, I have landed LongRangers and Squirrels in (big) backyards to pick up rich dudes, but that was in the 90s in Sydney. Don't think we would get away with it these days. And when operating police choppers in the 80s we could plop onto any sports field if the requirement was there, with an agreement from all the local councils.
Statements that CA$A is onside and "working" on a solution for Lili Pads across Melbourne make me laugh, CA$A is hard pressed enough to cope with the normal regulatory processes without spending time on the CGI daydreams.