Unless you are interested in originality, why not use a modern, fully sealed relay instead of the old Lucas relay? The reputation of Lucas electrical components is well known and well deserved.
https://www.digikey.com/product-detail/en/panasonic-electric-works/CB1A-M-12V/255-1828-ND/647020
Regards, Neil Tucson, AZ
https://www.digikey.com/product-detail/en/panasonic-electric-works/CB1A-M-12V/255-1828-ND/647020
Regards, Neil Tucson, AZ