casalinda, Hi...
My understanding is that you can ride a motorcycle up to 125cc (11KW max power) without restriction on your UK car licence.
Most of the answers to your questions can be found on the dgt.es website under the heading 'Tramites y Multas'
But, basically whatever authorisations you have on your current UK licence (if it's an UK / EU photocard licence) are also valid here in Spain; see this link...
A rough translation of the introduction follows;
'The licenses issued by Member States of the European Union, under Community law, remain valid in Spain, with the exception that the age for driving corresponds to that required to obtain permission Spanish equivalent, not. However, license holders who have obtained residence in Spain, can apply for exchange.'
The full listing of requirements for each vehicle group can be found here.
Note that of course all of the information is in Spanish, however I have found an excellent on-line translation site ; its better than babelfish and concentrates on Spanish-English -Spanish translations only. (This link, unlike some translation sites, is free from bugs and advertising and is normally only available to persons subscribing to the main site
Hope this helps...
fb
Edited to extend content and correct minor typo!
This message was last edited by foxbat on 17/10/2009.