Hi cornishmaid18, First you can hire a wheel chair from sidari, details in the post in information section.
They deliver and collect.
Secondly, you have a choice of two bike hire places.
Nikos (Pegasus), at the side of the Condor or Spiros as you know, around the corner.
Both will definitely do a deal with you and you should go to both to see which is better.
They always have Quad bikes in stock!
The Quad bikes are easy to drive and are Automatic.
Control done from the Handlebars - dead easy to drive - go slow round corners and try to avoid the potholes!! LOL.
The Theodosia Apt's are where we stayed in July.
The Downstairs Apts would be perfect for you and the slope is not too bad.
I pushed my Grandson up in his pushchair daily, no comparison, but it's not too bad and manageable!
There are a few other suitable Apt's around as well! With a Quad - you can go to many different Apt's!!
Hope this helps - just ask if you need more info!