based on this manual:

http://www.gdainfo.com/Resource1049853HJDUFOS023X/Owners%20Manuals/Dehumifier/GDH_DEH16Emanual.pdf

It looks like its a Dimplex item, sold by Homebase.

try here:

https://store.gdcgroup.co.uk/catalogue/dimplex/spare_parts/dehumidifiers/index.htm

You may need to contact Dimplex as it looks to be out of stock, alternatively there may be other online retailers with stock available. Check model numbers

Google is your friend

XXX
November 2015