The battery was bought as a replacement. So far it has been discharged and then recharged a couple of times with no issues. Fitting was fairly straightforward thanks to the supplied tools I was able to get at the fiddly and delicate parts of the PS Vita. Fitting instructions are not supplied but internet video sites are where I went anyway. From removing old battery to installing this replacement took 5 minutes, largely down to having the right tools (supplied) for the job.
A once forgotten and thought dead PS Vita now has life and a very happy 10 year old.