Not sure who maintains that tech site...but here are some other replacement parts that i have found over the years...mostly for RRC, but applicable to other Rovers too...
Here is a list of parts that "seem" to work OK when a Genuine part is not available.
Ignition Coil - Most parts chains have a number of options in-stock, including BWD E504.
Ignition Wire Sets - again, most chains stock something like the Denso set# 671-8139
A/C Expansion Valve - tough to find item for some Range Rovers Classics (89-94), try oreillyauto.com for Murray Part#38733 to replace the hard to find AC expansion valve on some early RRC's.
Main/Fuel Pump Relay- Try autopartswarehouse.com for Bosch part# W0133-1631929 to replace the silver 0 332 014 112 relays.
Cruise Control Vacuum Pump-a few options are out there. Look on eBay for a used Saab 900 or 9000 pump, you will have to splice your old connector on, otherwise perfect replacement. Check summitracing.com for Dorman#904-214, again you will need to splice in your original pigtail.
Heater Blower Motor - Try part # W0133-1652002 from partsgeek.com to replace Range Rover Classic Heater Blower Motor RTC6693.
U-joints for driveshafts on Range Rover Classic and Discovery, try Neapco Part No. 1-0005, available everywhere.
Ignition Module (Ignition Amplifier Module) - If you have your original ignition module it is likely a 2 wire connector. Newer replacements use a 3-wire connector (STC1184) and will require a cable to convert your 2-wire harness to the 3-wire amplifier. Or you could simply make your own. There are 2-wire version still out there as they are used on Austin Martins and some Fords (Fiesta?). You can find it under Transpro Part#LM122 as well as a number of others
'91 RR Classic
'01 RR 4.6 HSE - Gone!
'00 Disco 2 - Gone!
'95 Disco 5-Spd - Gone!
'92 RR County SWB - Gone!
'63 2A SWB - Gone!