Just a thought but have you moved since or changed address somehow (unlikely if you still need your deeds) so if they sent out the deeds to you you may not have got them?
Do you know if your property was registered at the Land Registry with a title number?
Compulsory land registration for Bristol was from the 1 Dec 1967 so if it was a normal sale the property should be registered.
If so, all the title info will be on the register. You can check here if it is registered...
http://www.landregisteronline.gov.uk/
What else may have been with the deeds that you may need as there may be other ways of getting hold of the info I may be able to help with.
Could they have also sent them to your lender? May be worth checking with them what they have.
If they can't help then contact the SRA...
0870 606 2555 (inside the UK),
09.00 to 17.00, Monday to Friday