Congratulations on being elected/re-elected to Parliament!
One of the most important things you must do right away is to register with the Information Commissioner.
It’s really easy to do, by going to their website here: https://ico.org.uk/registration/new and select ‘Elected representative’ from the drop-down list. Registration is free for Members of Parliament unless they process personal data for any purpose outside of their role as an MP. You can find further information about this here: http://www.w4mp.org/w4mp/w4mp-guides/your-office/freedom-of-information-and-data-protection-issues/
You can find lots of useful information about your rights and obligations under the Data Protection Act on the intranet here: https://intranet.parliament.uk/information-management/data-protection-security/data-protection/