This works, but I need to be able to construct the user object from the currently logged on user. Shouldn't be too difficult I hope !
var users = new Array(1);
var user = new Object();
user.AutoFillDisplayText = "Ian Chivers";
user.AutoFillKey = "i:0#.f|membership|[email protected]";
user.AutoFillSubDisplayText = "";
user.AutoFillTitleText = "[email protected]\nTenant\[email protected]";
user.Description = "[email protected]";
user.DisplayText = "Ian Chivers";
user.DomainText = "kwsservices-7c59c4bf8d655a.sharepoint.com";
user.EntityType = "User";
user.IsResolved = true;
user.Key = "i:0#.f|membership|[email protected]";
user.LocalSearchTerm = "Ian";
user.ProviderDisplayName = "Tenant";
user.ProviderName = "Tenant";
user.Resolved = true;
users[0] = user;
this.SPClientPeoplePicker_InitStandaloneControlWrapper(peoplePickerElementId, users, schema);