Lightroom Licence purchased via Wowcher

I purchased a Lightroom subscription via [removed by moderator}, a third party discount site and was provided with a link to download, but the voucher (discount code) didn't work.  Due to this, the distributor (Adobe presumably) upgraded me to the entire Master Collection from which to install Lightroom and provided me with a licence number for the product.  I've installed Creative Cloud and Lightroom trial, but can't see how to upgrade to a full licence without paying for another subscription.  This is so frustrating as the third parties are very slow to respond and I've been unable to find support online despite hours of research.

Any help would be much appreciated.