Afternoon Keith & Kathy.
Welcome to the hobby/obsession!
You might find
http://www.handicaching.com/ of some use.
I know that a cacher by the name of Cache on Wheels (Heather?) uses a mobility scooter to cache. If you can track her down she may be able to give you some helpful pointers and share her experiences with you. Her GC.com profile (through which you can contact her) is at
http://www.geocaching.com/profile/?guid=67f56150-3ee3-4a9c-acaa-a7aad35a2420.
I note you're based in Cheltenham. Mzeb
0nga has a variety of what should be some easy to access August events in both Cheltenham & Gloucester, which he's bookmarked at
http://www.geocaching.com/bookmarks/view.aspx?guid=63fc3ba8-f4cd-4c00-81bf-cf0fd3aef208.
There are also some CITO (cache in, trash out) events coming up soon in the area, such as the ones in Hesters Way Park and also at a nearby nature reserve (
http://coord.info/GC4H3V2 &
http://coord.info/GC4H3V2).
There are also semi-regular meets in the area, usually in pubs, such as this one -
http://coord.info/GC4HK0K.
I hope the above has been of some use/interest to you.
Happy caching!