Lynda, Mathraki are just a bit up the hill and have a lovely pool, and great hospitality. Our Eileen and eggy both endorse them so that is plenty good enough for me. We have spent a couple of afternoons there enjoying the pool and the company. New Tony (lol) stayed there and loved it. It will be fine, whatever you need.
In truth, getting to the Rainbow is not a big deal. That's where you are used to being, having stayed at Dionyssos, but believe me, it isn't far. Nowhere is far in Arillas. It is one reason (of many) why Jen and I adore it.
Have a great holiday
Phil