They will have a lot of certificates to issue at the moment

From their website
Coronavirus
Following the introduction of the latest measures to reduce the spread of Covid-19, we may not be able to complete orders within the published timescales.
To help ensure that our services are accessible to those that need them most throughout this period, if you are able to do so we would ask that you delay making your order until a later date.
During this period we will not be able to provide information on the progress of orders, but please keep checking this page for further updates.