How do I identify the owner of a garage shown in ‘blue’ on our title plan?

We are a group of 5 flat owners who each has its own garage at the rear of the properties with private access. There are 6 garages and 5 flats. The extra garage is shown in blue on the title plan. This additional garage is locked and bolted but its owner is unknown although he has left a note of complaint when a car parked in front of his garage. We are told that this is owned separately from the rest of the property. 

1. How do I find out the title deeds and owner of the separate garage
2. How do I check his access right across our property to the garage, if he’s not part of the ‘flat’ group. 

Many thanks

Ruth

Ruth - you can search online or by post for registered information. If you know the garages are all within the same freehold title number then search for that or use the search by map option.
If the garage is registered separately and has rights across other land then the register would normally refer