On the toolbar > Options > Composition > Send options Button

Uncheck the send messages as plain text if possible..

Send a mail. Better? No, use the drop down below the option to change the send option from both to HTML only. Better?

The second option does raise issues if your recipient can only read plain text messages. But these days those people are rare. They will soon tell you if you send them unreadable emails, because they get it all the time.

I am only referring to the received e-mails which are shown in a basic typeface rather than in the font that they were sent?

Are you viewing the emails in Plain Text mode?

If email was sent using Plain Text only then that is only available, but if it was also sent as HTML, then you have the choice of how to view it.

To use HTML instead. 'Menu icon' > 'View' > Message body as' > 'Original HTML'

You do not say what font was mentioned in the source of email: Select email click on 'More' and select 'View source'

If the font is not available then nearest equivalent will be used.

'Menu icon' > 'Options' > 'Options' > 'Display' > 'Formatting' tab Default font: select from drop down

This is then used as default font for both display and emails you create. The font is not hardcoded, so allowing the recipient to choose what font they have set on their computer. After all not everyone has the same OS or same fonts on their computer and some people may need to display in a manner they can read eg: if eyesight problems.

Click on 'Advanced' button. here you can eg: minimum font size.

you can also select option: select: 'Allow messages to use other fonts'

click on all Ok's when finished.

Thanks for your help, job done, great!