Snails as a resit suggestion

 I saw this photo of this 4th century mosaic (in the Basilica of Aquileia, Italy) and it reminded me that snails could also be a good choice.

CC image by Sailko

You don't have to use (and kill) "fresh snails" if you don't want to, although you can make life more difficult for yourself if you use very old abandoned shells, as they will have lost their colour and are more likely to be damaged - much harder (if at all possible) to identify.

Some of the snail collections this year (I thought) were really good - their creators had been out to a variety of habitats and so found a good number of species. Others weren't so good because they only contained a handful of species (submitting many examples of the same species isn't going to get you extra points).

I've been surveying plants at a local limestone grassland and I keep coming across snail shells (and live snails) - species you won't find in your garden.

Some species are a lot easier to identify than others. But once you've got a range to look at, you start developing an understanding of what the identification guides are getting at. There's one online at BRERC but I've found it much better to use it in combination with other resources (see here)
as some groups are particularly tricky and a range of descriptions to compare is helpful.
I've also bought a copy of this older book by Kerney and Cameron which you'd be welcome to use - the names can be a bit different but you can cross-reference with Cameron's newer book (which I also have a copy of).

You could come in and view your specimens under a dissecting microscope - it's useful to see the fine sculpturing of the shells. Or otherwise you will really need a handlens for the smaller species.