Thank you brezhnev. Following your very useful tip I googled the key words in your information and came up with the same web sites as you did. Now as a result of further googling I have sent off an email to try and get in touch with Brian Beasley who wrote the doctoral thesis to which your above link leads. I am hoping that this will lead to further hard evidence about a brave young Hull man who died at the battle of Jarama.
I think I shall start another specifically targeted thread to try to get the words for Jack Lindsay's poem Requiem Mass for Fallen International Brigaders.I shall keep you informed. Thank you for the lead.
Regards, Geoff