Some fixable validation (iframe is fine)
Too much space under copy and to the right on about
typography throughout needs a little work e.g. on about looks very empty and small, primary home page is a bit plain text, branding, web design etc seems a bit harsh and
title texts and H3 are nice though
That video – world’s smallest etc really does not work there – it looks really out of place
top margin padding on customer stories is very narrow compared to other titles – think consistency
It just needs going over and refining wherever possible rather than rethinking which is good
Given that is usually just an API setting I would ask the author it may well still be possible BUT I know for a fact that several (including a few of the biggest) property site sin the UK require express permission for your site to be able to aggregate their listings etc. so you might want to look at that first too.
This is more than likely going to need to be custom built. You might find some kind of membership/directory type plugin that does some of the work but even then it will need further customization to work exactly how you want.
Also if it is for a clinical or medial project you need to be 110% sure on security so a custom job will be much better here too