Hi Mandy and Welcome to the forum, you might want to have a look at the following FAQ which explains where everything is
Welcome to Benefits and Work The are some delays in ESA decisions, but I would have expected to have heard by now!
You have 2 options -
You can decide that ESA is still being paid and leave well alone (ESA is an indefinite award, so there is no risk of it ending before a decision is made).
Or you can contact the Assessment Provider (Maximus/ HAAS) and ask what is happening ( I had a prompt and courteous reply when I emailed them earlier this year).
www.chdauk.co.uk/contact-us