Drop-down menu extending into message box

On our website, we’re experiencing an issue with Contact Form 7 on mobile where the drop-down menu extends into the message box below and the user cannot select the box to input a message.

https://mapartments.co.uk/

The issue is only happening on mobile and not on desktop. Here is our code:

<label> Full name *
    [text* your-name] </label>

<label> Email address *
    [email* your-email] </label>

<label> Phone number *
    [tel* phone] </label>

<label> Where did you hear about us? *<p>
[select* source "Google or other search engine" "Social media" "Word of mouth" "Advertisement" "Media publication" "Other"] </label>

<p>

<label> Message *
    [textarea* your-message] </label>

[submit "Send message"]

Can anyone see what the problem may be?
Thanks
Samantha