Partack
According to what I can gleam from search results online, the laundrette is said to be #49 according to google.  I went to this house and it didn't have a number on it. Only a name.

However, when searching for #49 harbour road on "findmyaddress.co.uk" which uses official local authority ordinance survey maps, it says this house is #49 and it has a UPRN: "64022065" 

there is also a UPRN "64022076"
which ALSO lists this house but gives the address as

Celtic View
Harbour Road
Barry
CF62 5SA

OpenUPRN lists the laundrette as 
UPRN: "64022080"

and when searching that number on findmyaddress, it lists the address as

The Launderette
Harbour Road
Barry
CF62 5SA

So given this information, I propose we put both of them as #49 but also list their names in the address. That way, any delivery person (or ambulance) can at least be in the right area in a worst case scenario.

I have made the necessary changes and welcome anyone to make edits should this information be in error. I've tried to the best of my ability to resolve this note and shall now attempt to close it.