Sort by: Price – not working

Responsive Real Estate Theme V5.2

I am having no luck getting my search to ‘Sort by: Price’ and have now spent hours trying different solutions. I have created a custom field of:

Custom Field: Price
DB key = price

I have setup my general setup as:

General Setup> Search Results Settings >Display Order = Price (hig-low)

However, when I do a search, I get my results in the following price order:

10,000
22,000
5,000
15,000
27,000 (featured)
20,000 (featured)

I tried setting up Custom Orderby Settings in the hope it would overwrite the default:

Price (Low-High)[orderby=price&order=asc]
Price (High-Low)[orderby=price&order=desc]

But when I then select one of these ‘Sort By’ drop-down fields, all results are removed and the search results shows:

There are 0 matches

This makes me think that for some reason, there is some issue in that ‘price’ db entry is not being recognised as the price?

I have tried creating new listings in case the search was not picking up the previous data but this has made no difference.

If anyone can shed some light on this, I’d be most grateful.

Thanks