Yes I have done it like that as well.
This seller has a £6500 Ben Bunny listed and also a £400 1891 crown.
https://www.gumtree.com/profile/accounts/1ed6d119377f6b71f2bf25810d62b7c5
So I offered her 2 Ben Bunny and 2 Peter Rabbit in swap for the 1891 crown.
She said no and I asked her why she wasn't accepting over £20,000 worth of Potter coins for the swap I have had no explanation from her.
I've just sorted through £250 in .50 coins and found the exact same coin. It's listed in the Coins UK app:
>https://play.google.com/store/apps/details?id=uk.co.primalsoftware.coinsuk
Under "More > Territories > Isle of Man >"
Isle of Man TT, commemorating the Isle of Man TT races. The date range (according to the app) is 1997 - 1999, mine was from 1997.
I pay for a subscription to the app (.59 per month) because I find it to be useful, and want therefore to support the creator - included with the subscription is the ability to see how many users of the app have 'collected' a particular coin. Interestingly this one has been collected by approximately 13.21% of users, so it's somewhat unusual - however having looked in eBay it's not particularly valuable:
On top of the other suggestions, ebay sold listings and a book like this are your biggest assets - https://www.amazon.co.uk/Collectors-Coins-Decimal-Issues-Kingdom/dp/0901170402/ref=asc_df_0901170402/?tag=googshopuk-21&linkCode=df0&hvadid=535908754549&hvpos=&hvnetw=g&hvrand=8432947887022540944&hvpone=&hvptwo=&hvq...
That book covers UK coins, but won’t have things like the Hercules coins which I think are Gibraltar. The prices will be conservative, but it’ll show what has value above face value.
Bear in mind if you’re going to sell, the easiest solution (sell in one lot) will get you least money. Piecing it out will net you more, but will cost you time.
Try and get more than one opinion before you make any decisions.
avoid uPVC it’s will fuck your coins up good… i use coins flips and i have a storage box that allows them to stand there (see below)
I use one of these: >https://www.amazon.co.uk/COLLECTOR-Album-sizes-coins-small/dp/B073RMQPPJ/
However I've noticed the plastic inserts aren't the best - upon taking some of my coins out the individual slots retain an outline of the coin which doesn't bode well for long-term storage.
I think the albums themselves are OK but it's the quality of the sleeves that are important.
Card pages probably would work. But they make ones specifically for coin flips, so you could fit the max per page. Something like this (although I have no idea if this specific brand is good): https://www.amazon.com/Collection-Collecting-Protectors-Quarters-Currency/dp/B09MK89CXT/ref=sr_1_7?crid=3NVWCO426XGXP&keywords=coin%2Bpages&qid=1660319867&sprefix=coin%2Bpages%2Caps%2C68&sr=8-7&th=1
This book is a good start. There’s also one similar for grading which is useful as well. Try to focus your collecting, it’s really easy to get lost and sidetracked, although that can be fun as well. My attention is mainly on crowns, particularly George III and 1951 Festival of Britain, and compiling a bu/unc 1890 currency set. But then again, I still have many offshoots.
If it's pre decimal coins you're interested in, then Spink is the must have de faco standard.