Look for local cycling clubs - not all clubs are for the 'road racers' on carbon framed dropped handlebar machines.
Cycling UK, and U3A (for those of a certain age) are just some of a number of resources that could offer what you're looking for.
Down here we have for instance, Portsmouth CTC (Part of Cycling UK) who have rides for all abilities, and no differentiation is made between e-bikes or otherwise.