Just to follow up on this I finally got around to sorting it out in the New Year and had NR added to my Open24 account as a "bill payment" (using the NR account and sort code and my NR account number as the reference) and can no transfer money online. Unfortunately this is not a wire/electronic transfer and takes three days to transfer and there's a €10K daily limit on non VISA/utility bill payments but it's better than nothing (or posting cheques etc.). I did a test payment of €1 just to make sure that it worked OK as suggested earlier by somebody. Hopefully the electronic transfer in the other direction works OK when it comes to it! 
Thanks for the advice.
Thanks for the advice.