OMG. As if I wasn't spoilt for choice before! Thank you all for your comments. It is clear that I need to digest them all and enter all the specs onto a spreadsheet to make comparisons.
As a hirer of regular pedal bikes, we have gone with a fleet of Claude Butler - mid range in price with good pedigree etc. We are trying to stay away from suspension forks & disc brakes as the salt air has caused problems in the past and they are more effort re servicing / repairs.
I was unaware of motor wheel vs crank drive, so more homework needed. Wisper bikes keep popping up when researching - I like the fact that they have been adopted by police forces which would suggest reliability and durability.
As with everything in life, it all boils down to choosing the best spec & reliability that you can get for the money. Once we have the charging points in situ around the Island we will be moving into e-bike sales to the local and corporate market so volume sales discounts will obviously play a vital part in the decision making process.
Many thanks to you all once again... I'm sure that there are a million other questions that I will have, so prepare yourselves now and treat me gently!!