Is anyone else getting an error message when trying to access...

Is anyone else getting an error message when trying to access the SPP via Computershare? It's asking me for postcode and HIN but there is only one box and ay combination of postcode and/or HIN gets me an error message - if I only put the postcode it tells me the HIN is missing if just HIN or the HIn + postcode it tells me the postcode is too long.

I'm sure there is a simple fix but after 30 minutes stuffing around I give up. any help welcome.

thanks