Yes it is the Wellington Sports ground. I'm sure if Harry said it was ok to go down then it must be, however it was announced by the club last season that visitors were no-longer allow, so expect to be disappointed if you go. However I'm sure you will be able to see and speak to some of the players if you were to go.
PS Welcome to Talk Pompey, hope you enjoy the site, and if you do go to the training ground if you could post and let us know what happened.
Jen