I've got a google webmasters tool account with a website I help look after, they've employed the services of an SEO/SEM company* who have asked to add google/microsoft/yahoo webmasters tools accountsI don't want to give them access to my account (its tied in with other websites I have on webmasters tools) so my question is it ok/possible to have multiple webmaster tools accounts on a website?*The company are trustworthy, they've been great to deal with.
Multiple webmaster tools accounts on website
google search console
Yes, you can. A site can have multiple owners. You don't need to give access to your account, each owner can have its own account and verify it against the site.See Multiple Users.A site can have more than one verified  owner, and you can add and remove  owners easily using the Manage  Verification page. (Note: To add a  person as a user, that person must  have a valid Google Accountfor  example, a Gmail account.) These  owners will have all the same rights  as the original owner, including the  ability to add and remove owners.