If you look at one of your own listings, then switch to the Postage & Payments tab and change the postcode to your buyer's post code, then click 'Get Rates', the delivery time-frame will be recalculated and show how many days eBay "guesstimate" an item will take to get from you to a buyer in that postcode (including your stated handling time - don't forget to change the PC back to your own, or you may see incorrect postage quotes on listings using calculated postage etc). 

I wish eBay's estimates were either more realistic, or made it very clear they in fact are a third party estimate, by a company that has no involvement in the delivery process whatsoever. Issues like this are on the increase because buyers A) treat it like a guarantee and B) seemingly panic and (sadly) open disputes far too early. 

I believe an eBay rep recently told a seller that they should put a disclaimer on their listings if they wanted buyers to be aware the delivery estimate was just that (seller got a neg because an item was delivered past the "due date") - wouldn't have to if eBay didn't put the estimate there in the first place, then  leave it up to sellers to deal with all the consequences.