If anyone else is wondering I found the same BSPP fitting for less than half what you paid... $10.97 at HydraulicHoses.com......
9023 Fittings: NPTF to Female BSPP Swivel | British & Metric DIN Fittings
I don't know about $3,000, but I've replaced the hydraulic hoses on a few of my vehicles from Hydraulics Direct and gotten a good deal each time. Might save you some money if you don't have that $3,000 just lying around. Here's a link to their automotive hose.
I found a site where you can buy just the individual o-ring for hydraulic fittings. Here's a quick article about the different types of o rings if you're needing one made out of a specific material. The o-ring specs are listed on the page for each ring.
As long has they have the correct crimp specs for the hydraulic hose and fittings you are using. Crimp specs below.
Hydraulic Hose End Crimp Specifications
The Bsp tapered is pain to work with because no one have the fittings. I found this site and this one of site which will let to adapt out of either BSPP to NPT or BSPT to NPT and JIC. They both seem to carry these converting adapters.
I've never been a fan of british fittings