The problem of working out who is trading and who isn't is the same problem HMRC are going to have to determine too.
The first check is simple, multiples of New items that once sold get refreshed time and time again, no genuine private seller will be in that position.
But with secondhand goods you have to determine who just is clearing out vs who is buying stuff at car boots, charity shops or wholesale with intent to resell for profit.
The obvious thing for me is that with the genuine private house clearance, these are one-time sales and even if there are multiples as these sell the listing numbers will gradually diminish over a few months and not be replenished.
Any private seller will likely have a binge clearout maybe before and after Christmas or a birthday but once those items are gone it's likely the account will go quiet whereas the trader will generally tend to be more consistent.
But then you have collectors. This is a real grey area as on first glance they can be selling off large quantities of same/similar as their collection refreshes/refines. Some collectors are trading of course be it for profit or otherwise but many are absolutely not and it's those that will likely be caught out with any kind of enforced business account upgrade.
Apart from collectors, I think the majority of genuine private sellers would struggle to sell more than 300/400 items per year but I'm sure someone will disagree.
On my private account I've sold things for my wife, kids, parents, in-laws and cleared my grandparents house.
Total sales is something like 2500 items over a 17 year period, which included a large collection of automotive memorabilia (mags, books, brochures, manuals etc.) of around 1000 items that I accumulated over a 20 year period which took nearly 3 years to sell.
If eBay had say a 300 item per year limit and I thought I would exceed it I could have just opened other accounts in the wife and kids names I guess.
