Thanks DannyBoyD and all who have contributed to this thread. We got the details for payment for my husband back, I sent it in November. Most years were at class 2 but a few where he was out of work during the recession were at class 3.
I rang Newcastle this morning, phone answered immediately ( they are quite today apparently) I got a really helpful lady who talked me through payment through international bank transfer. She gave me IBAN and BIC and account name and i had to put in reference which was NI Number followed by IC and surname. I completed it today in the bank, they wouldn't process without bank address and account address but I could google both... so fingers crossed. She took account of the years I was paying on the account.
I sent mine a week earlier and I haven't heard back yet but she said it should be reviewed within the month and to call back to check. I intend to call back next week to ensure transfer went through.