Orthoptera as an Order includes Grasshoppers and Crickets. The following websites have photographs which may help you in your identification of sightings and/or photographs. The best bet is to key them out using the key in the Harley Books volume "Grasshoppers and allied Insects of Great Britain and Ireland" by Judith Marshall and E. C. M. Haes.
Guide to British Grasshoppers and Allied Insects, Field Studies Council/ Natural History Museum, 1999
A good general guide, convenient for taking out in the field. Grasshoppers and Allied Insects of Great Britain and Ireland, Judith A Marshall and ECM Haes, Harley Books, 1988
A very comprehensive identification guide covering all British and Irish grasshoppers, crickets, bush-crickets, earwigs, cockroaches and stick insects.
Another aid is the Collins Field Guide to Wildlife Sounds. This includes a CD which has recordings of the following species found in Cheshire:
Common Green Grasshopper
Field Grasshopper
Meadow Grasshopper
Mottled Grasshopper
Bog Bush Cricket
Most other Orthoptera species are included (Ground-hoppers don't stridulate) on the CD, as are many birds and mammals. Retail price is £16.00, but I've found the book at remainder / bargain book stores for about a fiver!!