There was a period I had a direct sales website for an exclusive brand of products I imported and distributed. I then used eBay to list some of the smaller valued products within the brand range to rapidly (and cheaply) increase brand awareness, and also hits for the website. The larger of the sales were then conducted via customer contact to that independent website. That scenario will only work though in certain circumstances.
I had a quick look and you have varying item types listed but from my experience I'd think if all same items offered on gumtree at a reduced total delivered cost , (maybe reducing by half of eBay fees for example), then the gumtree turnover would be similar to that of eBay ?
Since you've done all the work on your eBay listings already I'd leave them up and adjust pricing as market dictates and/or allows, considerate of the profit being worth the effort obviously. In line with comment above if for no other reason than attracting more hits.
I often need use google to find details about items, spec's, model particular, or used pricing, and over the last couple of years I'm finding gumtree is much more prevalent in the search hits - especially if you search "images". I've been surprised to find my own images from gumtree sales of years prior to come up near top of image hits.
Your line items look to me like you'd attract very particular customers that either really want the item...or don't. That's a good thing in regard to allowing price adjustments.
I have seen mention on here about Etsy in regard to handmade items. Not sure but maybe some of your artwork would be suitable. If within applicable export laws your Aboriginal art looks to have good export potential too. I just did a google search using part of one of your listing titles : "Vintage Anna Australia Pottery " . First and second hits are eBay and the fourth is Etsy.
Maybe some more google searches will come up with more viable options.
