There are four steps that you need to follow to have any document issued in the United Kingdom legalised for use in the State of Qatar
The first is to get the document legalised by the Legalisation Office in the UK. The second is to have your document legalised by the Qatar Embassy in London. The third is to have the document legalised by the Ministry of Foreign Affairs in Doha. Once the FCO-UK signature is attested at the Qatar Embassy in London you or your employer can take your document straight to the Ministry of Foreign Affairs for attestation.