Jumping in because I just went through a similar thing and it was an amazing learning curve! I get really nervous about security with my main account, so I spent ages looking for the safest way to do this. I think someone told me that using the Wish List feature is the most secure way, though I am not 100% sure if it handles 40 items perfectly without some manual clicking. I love it when these things actually work out without compromising your data!!

• Try the Wish List method first since its totally free and native to Amazon
• Be super careful with browser extensions that ask for permissions to see all site data... I have heard some can be sketchy
• Always double check your cart total after importing because iirc prices can jump around during the move Its such a fantastic feeling when you finally get that bulk buy sorted without any glitches! Let me know if you want to chat more about keeping the account info safe.

i have dealt with this same headache before. the native tools are basically useless for more than one item. here is what works:

• Share-A-Cart extension: this is the most reliable one i have used for Amazon UK. it creates a code to sync the whole basket.
• CSV export scripts: some chrome extensions let you grab ASINs into a spreadsheet which is decent for bulk edits. for anyone shopping with friends or doing a gift list, Cart to Link is worth trying

To add to the point above: the security stuff is definitely something you gotta watch out for, especially with weird scripts! But man, when you get a solid bulk tool working it is actually amazing how much time it saves. I have been messing around with these kinds of workflows for years and there are some really robust ways to handle it without giving away the keys to your kingdom. Just saw this today and wanted to jump in because I love optimizing this stuff. Before I drop my favorite reliable setup tho, I gotta ask... are you looking for a one-way dump where they just receive the list once, or are you looking for a more collaborative thing where you both see the cart updates in real time? It makes a huge difference in which tool is actually gonna stay stable for you!

Honestly, I tried a few of these one-click cart sharers a few months back and it was a total disaster. I'm always super paranoid about my account security, and unfortunately, most of these tools felt really sketchy. One extension actually made my browser crawl and I started getting weird login alerts from Amazon UK. Not fun at all. If you're doing a bulk buy of 40 items, you gotta be careful with a few things:

• Extensions that ask for read and change all data permissions. That's a huge red flag for me.
• Tools that dont handle regional UK links properly. I had one that kept switching my currency to USD and messed up the whole order.
• Bot detection. If a script adds 40 items too fast, Amazon might lock you out for a bit. Since I'm always trying to save a bit of cash on big orders, I usually run everything through Price Drop Catch first. It tracks prices across Amazon and eBay and lets me know if I should wait a day or two to save a few quid. It's way safer than those weird cart-scraping scripts tbh.