Or get your starter rebuild. Not expensive at all and better quality than a cheap new one. The guy I use also cleans the case etc, you can hardly tell it's not a new one, typically not even €100. And he has most types in stock, so when you turn the old one in, you get another one that is already rebuild straight away. You could even do the swap on his parking lot, should you need to.
As for the parts you list, RTC5050 is for the previous generation of V8s (RRC, Disco, Defender), rtc834 for an even earlier version. So I don't think those would work on the P38, you'd need STC1241
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Some good advice, don't just look at Ebay sellers, they often don't know what they're selling. You can find all the part nr on
Search Genuine Land Rover Range Rover 1994 - 2001 Classic Parts | Jaguar Land Rover Classic Parts. That way you know exactly what you need and don't have to rely on fitment charts etc.
Filip