I have a little update for anyone interested – after checking all the above we reverted to our webhosting company who said the following (my kid web designer will be getting on the case and I will let you know if it solves the issue):
We are blocking some web “Bots” due to their often aggressive crawler techniques which impact on both bandwidth and server resources: Some Aggressive or Bad Bots We Have Blocked To Our Shared Hosting Network of which Facebook is included as part of that.
This block on Facebook/Meta bots may be lifted by adding the following rule to your websites .htaccess file:
# Whitelist Web BotsSetEnvIfNoCase User-Agent facebookexternalhit/1.1 WhitelistSetEnvIfNoCase User-Agent meta-externalagent/1.1 Whitelist
