David Davis asked whether consulates abroad keep records of the offences, sentences, names, passport numbers, or DNA samples, of British criminals convicted abroad. Crucially he's also asked what procedures exists to transfer this sort of information back into the UK for dissemination into the relevant Home Office agencies.
In response, the Foreign office confirmed that Consular staff do record offences and details (with the exception of DNA and fingerprints). The Foreign Office minister Kim Howells also confirmed that,
"when posts overseas are informed of the arrest of a British national, details of the arrest are entered by consular staff on the Foreign and Commonwealth Office central consular assistance database: “Compass”. Compass allows real time case management by staff overseas and in London, including details of convictions when known, so the separate transfer of records from consular staff overseas to the London Consular Division is not necessary."The implication of this is that not only did the Home Office fail to act on lists provided to it by ACPO, but that the Foreign Office records the information and then fails to get the information added to British criminal record databases too. On the basis of the above answer, the Foreign office would've known about the British citizens convicted abroad as well.