Steve,
If your ding is currently small enough to be repairable, I'd recommend getting it done now ...
From Dave Bean - windshield $679.80, shipping $180, trim - corners $13 (1 piece cut in half to make two corners), top $38, sides $19 each.
From Pilkington Classics - windshield $535, shipping $110. Before quoting they asked if I was a shop - answer was no, an individual owner. If I go with a shop I would expect they could get it for less.
In addition, the following are needed per the manual the write-up linked below: Betaseal Kit A075B6158J and Mirror Plinth Kit A100B6230S - I'll check on their availability.
A great write-up on the procedure here by saska
forum.lotuselancentral.com/viewtopic.php?f=32&t=6529#p231147, and the repair manual has detailed instructions. As the procedure has enough time consuming details, as a careful, takes my time, DIYer I'm tempted to do it myself, instead of trusting it to someone working against the clock. The trade-off would be my willingness to take all the time it needs (but I haven't changed a windshield before) vs. someone who's done it many times, but can't / won't spend the time. I have to say that looking at it again just now, freeing up the bottom of the windshield looks like it would be a cast iron b!tch of a job.
In my case it appears the mirror anchoring location may have been the culprit. The crack starts there (in the inside layer), and spread to both the drivers and passengers side, with a couple lines straight up to the top windshield edge also.