A little googling found this:
FRONT WHEEL BEARINGS (One Side) Ford Prefect E93A 100E & 107E 1938-1961 - ÂŁ38.00. FOR SALE! A set of inner & outer front wheel bearings (one side) for the following Ford models:Anglia: 1939 - 1953 Anglia 100E 1953 - 1959 (to 783800) Popular: 1953 to 1959 Prefect:1939 - 1953 Escort & Squire 1956...
picclick.co.uk
from which it seems like what you want is
Timken 07098-07205 (inner) & 03062-03162 (outer)
Googling the first number (just the first hit)
07098-07204 Tapered roller bearings. Inner Diameter: 24.98, Outer Diameter: 51.99, Width: 15.01, Weight: 100.
www.sp-spareparts.com
Making me think they aren't cheap anywhere.
BTW a quick thought - if you could put the year and model of the Prefect in your signature, then it makes it so much easier to respond. Click on your name on the menu bar and then click on signature in the drop down menu.