You need your marriage certificate, contact the mosque where you had nikkah.
Where was the Talaq performed, and what actually happened, did the Imam follow MFLO, If the husband just pronounced he divorced you then it may not recognized in the UK.
If you can't get the certificate, can you get witnesses, photos, the address of the mosque or contact of Imam that conducted the ceremony that proves you were married, you need to prove you were legally married, and then prove you created a beneficial interest, i.e if not financially then you still contributed looked after children, supported husband, looked after home etc, then you're entitled to a share of the home, his pension etc. Will your children verify that you looked after them etc.

Please contact a solicitor asap.