When I enter the site, I've several logon details as a result of 'fat fingers' and have to view down them to find the correct one. Anyone tell me please how I can delete the spurious ones?

Simples. Ask Xileno/leasema from that email address and username to block any adresses you don't want to use.

How do you think spammers are stoppe.

Then clear your cookies and site settings and check in your browser settings that those email logins are not saved.

Passwords same thing.