Hi Jackie
I’m so sorry I had forgotten I put this post up or I would have come back and closed it.
Thank you for your response. While I was waiting I decided to give it up as a bad joke because I was having other hosting issues, like not being able to access FTP (helpful!). So by the time you accessed the site I had moved it to another host and it was in maintenance mode using the ‘Maintenance’ plugin.
It all seems to be working fine now – I haven’t had any issues since moving it to the new host so I’m putting it down to the host having server issues. The client is now happy, which is the most important outcome! Thanks again!