Never done anything like this before, but found a straighforward generic video on Youtube which explained how to replace the existing 1GB memory, which took me about 5 minutes at most.
Replaced the battery, and re-booted the machine, and everything worked as before, but with a marked improvement in speed, and more than met all expectations for a very reasonable price.
Amazon's order handling/delivery performance was as I have always found without fault, and having had some, albeit minor, problems with other on-line retailers, there now has to be a very significant price differential for me to consider buying elsewhere, although I generally find Amazon extemely competitive on most items.