how on earth do they get in positions like that ?
Only eBay knows and they're not telling, for obvious reasons!
they don’t do what eBay tell everyone to do , less than 6 pictures / on any background,hardly any item specifics filled
If you have highly desirable items, you can have bad photos, poor title, missing details, et cetera.
My understanding is that the Best Match is the eBay algorithm showing you what you're likely to buy. Top search spot goes to a Priority Promotion, then come the General Promotions. Promotions are not available for 100% so different listings will appear towards the top at different times. Just by focusing on and clicking into this other Seller's listings you may have caused them to appear first for you!
Other observations and speculations about the eBay algorithm:
eBay seems to reward new Sellers with a brief flurry of sales
eBay seems to reward Sellers who consistantly list with higher search appearance
One Seller had some interesting data on YT recently: Justin Resells 'How eBay Controls What You Sell'.
yet I’m paying a fortune in promoted listings just to try and get on to page 20 !!!!
Speaking of data, currently eBay UK promotions are not linked to sales (direct or halo), this makes it difficult to judge whether paying a fortune is worth it.