Thanks again everyone for your help. I tried booking into Casa Lorenza but they didn't have the dates we wanted. I have booked a studio apartment in Riomaggiore that is on the first floor. No sea view but at least I won't have to climb 5 flights of steps a couple of times a day. If it turns out to be good I'll certainly let everyone know here.

We stayed in Riomaggiore in Affitcamere alla Marina in September this year. Our room was on about the 5th floor but maybe you don't realise that this is the level of the station and most of the town. You only drop below this to catch a boat or wander around the boats or eat in two or three restaurants. The path goes from the other side of the station i.e. the same level as you enter the B&B. There are two entrances and we only went down the 5 floors of stairs to go to one of the particular restaurants. After eating we would wander back up through town looking for coffee and ice-cream and always end up higher than the lane entrance to the place. The lane entrance actually took you in one floor above our room- if that makes sense!I have an aversion to hills (its called being lazy!)but I'm very glad we stayed here.
The B&B has a s/c apartment which I think is at lane level
The accom. itself was lovely but the view and being able to look out of the window on the life going on at all hours, was magical. I was even getting up in the night to look out if I couldn't sleep!
I highly recommend this accomodation.

I wish someone had told me this before I booked. Anyway its done now.

Know you'll have a great time, jenmorg. It's less about where you stay than what you end up doing, probably! Glad you looked into Casa Lorenza,though.