Postage via eBay's Simple Postage - I only use Royal Mail Tracked 48 unsigned - I do not use Evri. This gives the cheapest prices and provided automatic tracking.
Collections by appointment
Postage discounts - I use eBay Simple Postage which restricts how postage discounts can be given, you are buying postage from eBay not me, and you have to request postage discounts at the checkout before paying - I ask you to do so - but if you pay I can't give you a retrospective discount, and will send items separately so the tracking works. This is also how the postage discounts work for GSP purchases.
Remember ask for for combined postage at the checkout before paying.!