Don't give up if you'd still like to host a Do.
I started attempting the NY Gayla shortly after attending PHL in '04. Response seemed tepid the first time I suggested it and picked up markedly the second time because there was more lead time (seriously, a year is not a bad idea) and people also were a bit more familiar with me.
I think there'd always be call for a London Do - but people from North America will probably need more advance notice.