These are simple easy-to-use pictorial guides which might omit species less likely to be seen. They focus on Leicestershire and Rutland, but no doubt most species will be seen in Hampshire and Dorset as well. The full list of their guides is here: https://www.naturespot.org/IDguides
This is just one of over 90 short concise guides, sold as laminated folding cards ideal for use in the field. They are listed at https://www.field-studies-council.org/product-category/publications/?fwp_publication_type=fold-out-guide However, the first three pages of each can be viewed online and are just about legible.
These are usually run by small groups of one or more enthusiasts.