Have two of these not big and no insulator so make sure switched off or battery out https://beaumvape.co.uk/product/beaum-silicone-squonk-510-refill-bottle/
Also one of these bigger capacity and insulator soon have another https://ecigone.co.uk/products/vandy-vape-pulse-x-30ml-refill-bottle?variant=32139251417133
Vandy vape sometimes on ebay £10 no postage ecig work out just under £13 with postage,shop about, the wee Baume vape ones are fine, for carrying a top up about.