Hi, I emailed the developer and he emailed me the plugin later that evening.
However, I was disappointed with it and have found a free plugin since that does basically what I need it to do.
What I needed was a date picker that allows the user to select the day that they want to attend a free trial of a fitness course. I have a timetable on the site that shows the days and times so all I need to give the user is the ability to select a date.
The problem with the plugin as far as I can understand is that you have to create a separate post for every date/time you enter which in my case would mean at least 500 separate posts which not only would take hours but would be a nightmare to make small changes to a time.
I found a Delivery Order Date plugin that puts a datepicker on the checkout page, it's not ideal but with some customisation (change the labels) it suits the purpose.
I asked the developer for a partial refund as I can't see how it will be economical to use their plugin unless you just want to show a few dates, it's limitations should be made clear in the guide. I had an answer of no and then no reply to my follow up email where I suggested improvements.
With a bit more work it could be made to be a great plugin but as it is I have no use for it.
Hope that helps!