Are there any other people in a similar situation as me? What are your plans moving forward?
I'm effectively in the same boat, though over here the tax rate on DVDs and Blu-rays is "just" 21%. Nevertheless, the handling fee, additional delay and sometimes poor handling, makes it less enticing to import things. My key advice would be to simply factor in these additional costs whenever you purchase something. For the most part that means that most deals aren't deals anymore and only the really great deals become okay deals. Also try and bundle stuff to at least make the handling fee proportionally smaller.
As for where to buy, I would suggest to stick with Amazon for now. While I hate that advice, at least you know what you get. With other retailers, we'll first have to see that they do not charge VAT and properly declare the value. I wouldn't be surprised if they end up declaring the amount including VAT, or including the shipping cost in the value, split the order (and potentially declare the full amount on both parcels!). Not to mention potential issues with returns or replacements. In time it will probably become clear which retailers do it all correct, but at least for the coming months I'll wait and see how things develop.
Not sure if this applies to where you live as well, but if importing goods are exempt of tax under a certain threshold, certain items might end up
very slighty cheaper. In my case, anything with a value under 22 euro is exempt. So if I buy something off Amazon (or, in theory, any UK retailer) that is below this threshold (without VAT) I won't have to pay import tax. Some quick math and verification on Amazon.co.uk shows that ordering any DVD/Blu-ray in the range of ~17 to 23GBP works out cheaper (by a couple pence). If, like me, you tend to only really buy CEs, than that price range doesn't help much, sadly. Also worth nothing that other product types don't benefit from this as their shipping cost is higher and especially for books, as there is no VAT on them to be subtracted.
On the subject of books, I'm slightly torn on what to do. I used to buy books off bookdepository and wordery quite often. But both of them are situated in the UK. Now, I can continue doing that, but it would work out significantly cheaper if each book would be sent out individually. While a giant waste, I'm contemplating to order books one by one of these sites from now on, just to be sure they are sent individually. (Though recently I've also been buying German releases, and since they have a fixed price, I can just buy them whenever instead of waiting for a coupon a deal. So I might end up doing that more instead)
Of course I could just continue purchasing from the UK and pay the 25% customs duties but at that point I might as well just start buying from the US instead since they also have a bigger selection...
It never hurts to consider importing from the US as an option. Though if things would work out roughly the same price, I'd personally still pick the UK, just for the reduced shipping time and (hopefully) easier returns/replacements in case something does go wrong. When importing from the US, it can be worth it to check out different retailers, as some even reship from somewhere in the EU or undervalue goods (questionable). This thread (
Anime retailers No Import Fees List) list some of them, but be warned that the information can be outdated, or in certain cases the reshipping might actually occur from the UK
With Kickstarter you'd often see the same pattern, where EU orders were fulfilled by an UK fulfillment agent. I hope that in time other EU countries will start taking that role, but I'm not very hopeful, since the UK was a natural fit both as target audience of the Kickstarters and communication due to the language.
Another option is to broaden your horizons and look into releases from other countries. It's never too late to learn a new language

My collection consists mostly of UK releases, closely followed by US, but then it's a close call between German and Japanese releases, followed by Spanish, Italian and French. Now, becoming a polyglot for your hobby, might be a bit excessive. Instead if you're a bit tech savvy it's possible to put any subtitle under any video. Sourcing these subtitles can be questionable and the experience is definitely no longer plug 'n play, but it is an option.
Obviously there are various downsides to this. If you don't understand the language most extras (e.g. booklets) become useless, it can be hard to find information about the video quality and possible other issues with releases, which retailers are the best for which country's releases is yet a whole other journey, etc... The biggest advantage is the broad selection of releases to choose from. You can even buy your favourite show over and over again
Some quick bits of advice. German releases tend to be expensive (and in volumes) and in certain cases they translate the onscreen text(!) Generally I'm quite impressed with how they do it, but would still prefer an unaltered video stream. Italian publisher Dynit has some great releases (more info over on Blu-ray.com:
The Offical Dynit (Italy) Thread). Kazé is still Kazé in all countries they operate in.
Anyway, sorry for the long post, but hopefully it can be of some help. I think the best thing to do is to share findings and experiences going forward.