It would probably help if you had his date of birth when searching the 1939 Register.

Horrabridge is in Tavistock RD in 1939, so you could search by narrowing it down to that area.

If using FMP to search, you can use Horrabridge as a keyword.

By putting 'Bedford Road' into the street name (which is where 'Old Bedford' was if Google is correct), it does bring up some hits but paging forward gives some more hits in Bedford Road. No Fredericks, though.