SP2013 & SQL2012 - An exception of type System.Data.SQLClient.SQLException was thrown

Hello All, I recently upgraded my SP 2013 environment to SR1 the install went fine but when I try and run the SP Configuration wizard I get the following error  

Exception: System.Data.SqlClient.SqlException (0x80131904): A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: TCP Provider, error: 0 - No such host is known.) ---> System.ComponentModel.Win32Exception (0x80004005): No such host is known   at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection)   at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection)   at System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection)   at System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)   at System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource`1 retry)   at System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry)   at System.Data.SqlClient.SqlConnection.Open()   at Microsoft.SharePoint.Utilities.SqlSession.OpenConnection()   at Microsoft.SharePoint.Utilities.SqlSession.ExecuteReader(SqlCommand command, CommandBehavior behavior, SqlQueryData monitoringData, Boolean retryForDeadLock)   at Microsoft.SharePoint.Utilities.SqlSession.ExecuteReader(SqlCommand command, Boolean retryForDeadLock)   at Microsoft.SharePoint.Utilities.SqlSession.ExecuteReader(SqlCommand command)   at Microsoft.SharePoint.Administration.SPLock.ReleaseStaleLock(SqlSession sqlsession, Int32 timeoutInSeconds)   at Microsoft.SharePoint.Administration.SPLock.CleanupStaleSession()   at Microsoft.SharePoint.Upgrade.SPManager.AcquireFarmUpgradeLock(Boolean bForce, Boolean singleClickInstall)   at Microsoft.SharePoint.PostSetupConfiguration.InitializeTask.Run()   at Microsoft.SharePoint.PostSetupConfiguration.TaskThread.ExecuteTask()

I have read all the posts on this forum and others and I have made sure that the user is be a member of theSharePoint_Shell_Access role on the configuration database and a member of theWSS_ADMIN_WPG local group on the computer where SharePoint 2013 Products have been installed. And that in SQL the user have dbcreator and securityAdmin as well as adding sysAdmin but I still get the same error message

I have been going through the logs and the data source is pointing to an alias SPUAT1 

"ConnectionString: 'Data Source=SPUAT1;Initial Catalog=SPUAT1_ConfigDB;Integrated Security=True;Enlist=False;Pooling=True;Min Pool Size=0;Max Pool Size=100;Connect Timeout=15;Application Name=SharePoint[psconfigui][1][SPUAT1_ConfigDB]' Partition: NULL ConnectionState: Closed ConnectionTimeout: 15 "

I have created a link.udl file and tried to connect to that database but it times out but i am able to connect using the full server name??

I should add that I did have all the SP UAT serves in a High availability group but after trying to run the spconfig with them in i was getting a different erro so i took them out of the HAG and deleted the secondary databases 

Can anybody help me with this?

Many thanks in Advance

J