You won't find them at the auto parts
store. By the part number, yours are the larger Lucas 33ra relays and not the smaller 28ra relays commonly found on automobiles. They are also 24 volt. Probably 40 amp. Google
and that part number will take you to a seller of originals or a cheaper replacement. If you wanted to go to the trouble, you could rewire with the cheaper and much more common 28ra 4 or 5 pin relays. These are SIMILAR to those used in automobiles to control heat and A/C and horn. You would need 24 volt versions of the relay. Which area available, but not common to automobiles.