Thanks for your enquiry.
Have you checked at the Land Registry as to whether the garage is registered?
No how do I go about it please
Most properties are registered at the Land Registry.
Any person can apply for a copy of registered Deeds by logging on to the Land Registry website, quote the address and pay a nominal fee (deeds are known as "Official Copies").
As you are of course wanting to search against the garage, as opposed to a house with a postal address, I am not sure, to be honest, whether the Land Registry website service will be able to locate the garage readily.
If so, if you are willing to give me the address of the property (I assume the garage is located next to the property), I can carry out a further search for you.
Here is the link to the Land Regstry website-
I hope this assists you.