Change a couple of links in a Wordpress site

General information for the website: Holiday Cottages website
Description of requirements/features: www.burltoncottages.co.uk has a booking widget on the left on 5 pages (the Home page and the 4 Cottages' pages) and a booking link in the red header, at the very top, on all pages.

Currently, they both point to:

https://secure.supercontrol.co.uk/availability/availability_weekly.asp?dDate=01%2F01%2F2017&cottageID=cottageID_98326&Submit2=GO&ownerID=4852&siteID=15634&TID=&map=&__utmx=&__utmk=&loadcal=1

(where only one cottage is shown)

But they need to point to:

https://secure.supercontrol.co.uk/availability/availability_grid.asp?ownerID=4852&siteID=15634

(where all cottages are showing)

Thanks. :-)
Extra notes: