Thanks I will check and let you know
Apparently this is a spoof email.
Fasthosts want me to add an SPF record to the DNS Domain, however because the name is ***** ***** clook.net I have to approach them to do it. Will give it the old college try but this is now getting outside my expertise.
They also suggested I reset the email passwords and run some sort of malware detection on my Mac. Would you have any advice about this?