Would I have to pay income tax in Spain on my civil service & small railway pensions, at this moment in time I pay UK tax on those pensions also I have no other income coming in. Also will I have to contact the Spanish tax office about this as I am a resident here.

If you are living here permanently you should declare for Spanish tax and now is the time. You will be given papers to send to the UK tax office and they will issue a code of NT (No tax) so pensions are paid gross and then declared in Spain for taxation.

HOWEVER - there is an exception to this and from what you say you are in that category - any Civil Service pensions (plus armed services and maybe other government types) can only be taxed in the UK.

But I still think you should register into the Spanish tax system (you cant be taxed twice) otherwise you cannot have the benefits - residencia is not enough.

Visit:

SPANISH TAX (AEAT)

http://www.aeat.es
Mostly in Spanish but you can download forms (solictudes/modelos)

Non residents:
Ir al portal de:
Select and click

Or:
http://www.agenciatributaria.es/wps/portal/DetalleTributo?channel=a209e65a357ce010VgnVCM1000004ef01e0a

Under Other Services ? download Non Resident Income Tax PDF file.

Residents:
Click: Ciudadanos

Try also:
http://www.spainaccountants.com