[TYPO3-english] Images in powermail emails

[Simon Browning]

Hello.

We are trying to add a clients logo to a 'thank you' email from a powermail form.

However, when the mail is received the url part is removed, so there is a broken image (for example, instead of the src being https://mywebsite.com/fileadmin/images/logo.png it is https://fileadmin/images/logo/png).

We can see the url is present in the src of the rte, but it stores in the database without it.

Does anyone know of a way to get the url to remain, so that the email can display the clients logo?

TYPO3 7.6
Powermail 3.13

Thank you

Simon