English Springer Spaniels are WONDERFUL dogs. I had one in the past who lived to be 15 yo. She let every kid in the neighborhood use her as a pillow for napping and drinking bottles. Everyone cried when she passed. They are affecionate and kind.
Right now I have two Airedales which I think, if you have "aches and pains" you may not want a dog with a lot of energy and requiring exercise, but they do become real members of the family. You would need to specify that you want a smaller one of the breed. I have one that is almost 90 lbs. They do come in around 50 lbs also.
In either case, I would contact the rescue association for the particular breed you want.
You can google just about any breed on the Internet and find out about their sizes and personalities so that you get one that is suited for you and your lifestyle before contacting the rescue associations.