SQLite with mvvmcross

I have an SQLite database set up within my mvvmcross android application like this

public class DataService : IDataService
{
    object dbLock = new object();
    readonly ISQLiteConnection connection;

    public DataService(ISQLiteConnectionFactory factory)
    {
        connection = factory.Create("mydatabase.db3; New=true; Version=3;PRAGMA locking_mode=EXCLUSIVE; PRAGMA journal_mode=WAL; PRAGMA cache_size=20000; PRAGMA page_size=32768; PRAGMA synchronous=off");
    }

within my HomeviewViewModel, the database is set up and the tables inserted. There are no issues there.

When I come to insert into the database, any calls to connection.Execute results in the app crashing with an error to say that you can't execute on an unopened database.

The insert/update looks like this

    public void AddOrUpdateContacts(List<Connections> contacts)
    {
        foreach (var sr in contacts)
            AddOrUpdateContacts(sr);
    }

    public void AddOrUpdateContacts(Connections contact)
    {
        lock (dbLock)
        {
            using (var sqlcon = connection)
            {
                sqlcon.Execute(Constants.DBClauseSyncOff);
                sqlcon.BeginTransaction();
                try
                {
                    if (sqlcon.Execute("UPDATE StoreItem SET Id=?, " +
                            "Name=?, Phone=?, InviteSent=?, InviteAccepted=?, CanShareWith=?, TypeOfContact=? WHERE Id=?",
                            contact.Id, contact.Name, contact.Phone, contact.InviteSent, contact.InviteAccepted, contact.CanShareWith, contact.TypeOfContact, contact.Id) == 0)
                        sqlcon.Insert(contact, typeof(Connections));
                    sqlcon.Commit(); 
                }
                catch (Exception ex)
                {
                    #if DEBUG
                    Debug.WriteLine("Error in AddOrUpdateContacts - {0}--{1}", ex.Message, ex.StackTrace);
                    #endif
                    sqlcon.Rollback();
                }
            }
        }
    }

I've used this code in non-PCL and Xamarin.Forms apps without a hitch. When I check connection prior to the Execute call, it is correctly set.