Following my moment of recklessness the other night, I have been able to find a much more recent backup file which has now been restored. All posts up to the start of May are back, and I have kept the ones I entered in May.
I will still be working to restore the missing posts I have entered in May; at this point I am down only six posts which I will try to get back. The SQL Installation ones I may need to rewrite, but I still have the screenshots so that shouldn’t be too difficult.