Richard Palethorpe

Provides a block which embeds a <a href="https://dobu.uk" rel="nofollow ugc">DoBu.uk availability calendar and enquiry form</a> 
for a given nick name.
See the above link for a demonstration.

DoBu.uk Availability

Embed DoBu.uk availability and booking calendars

eGwada

The Openbookings Calendar Plugin displays booking availability of an object defined in your openbookings.org system.
A full calendar year is displayed, with booked dates highlighted starting from now.
You need to have installed openbookings.org on the same database as WordPress (see http://openbookings.org © for details

Openbookings Calendar Plugin

The Openbookings Calendar Plugin displays booking availability of an object defined in your openbookings.org system.

DoBu.uk Availability vs Openbookings Calendar Plugin