Is your property registered at the Land Registry?
If not then you should keep them somewhere very safe. In any event deeds often include more than just title documents so they should be kept safe in case anything is needed for a sale or remortgage.
If unregistered, it may be worth checking if a solicitor can do the first registration for you then keep hold of the deeds.
I don't know many solicitors who charge a fee for storage if they've done some work but they may send them back to you.
You could do the first registration yourself. If you ring the Land Registry they should be able to guide you in the right direction and the form (FR1 is available to download from their website).
Should only be �40.00.
http://www1.landregistry.gov.uk/