It sounds like the search is giving you the results you are asking for: results that have Austin Healey in the title or item-specifics in the parts category. Presumably the problem is that some sellers include that name in items that are unrelated to what you are looking for, such as key fobs.
Try some alternative searches to eliminate those unwanted items.
Try using an exclusion term such as -fits. That will eliminate titles that tack on "(fits: Austin Healey)" at the end, though it may also eliminate other items of interest as well, so be careful using this technique.
Try using some of the filters on the left side of the search results. If you are looking for parts actually made by Austin Healey, select that Brand, or whichever brands you are actually interested in. Checking most brands but leaving "unbranded" and "not specified" unchecked will eliminate much of the generic junk.
Try limiting your search to "used" items if you are looking for parts removed from actual vehicles, rather than new items. This should eliminate a lot of listings for things like aftermarket weatherstripping.
Or try using the "Vintage Car Part" filter option.
Try limiting your search to particular parts, or categories like Interior or Exterior parts. It may be easier to perform several searches of individual categories rather than one big search of everything.
You may have to combine several different techniques, depending on what you are looking for.
One possible starting point:
https://www.ebay.com/sch/6030/i.html?_oaa=1&_dcat=6030&_fsrp=1&rt=nc&_from=R40&_nkw=austin+healey+-f...
Another, minus the exclusion term:
https://www.ebay.com/sch/i.html?_from=R40&_nkw=austin+healey&_sacat=6030&LH_TitleDesc=0&_fsrp=1&Bran...
If you actually want to find every possible Austin Healey part and not miss any at all, you may have to wade through some unwanted results to ensure that nothing slips by, unfortunately.
