I think you should listen to the Panasonic system before buying it and decide whether it does what you want. Although your existing kit is old and the speakers are a mish-mash, it suggests that, in the past, you had designs on a separates system giving you a certain level of power and quality.
Judging from the magazine review, the Panasonic system is very good - of its type. If you're happy with it, fine, but do check that it doesn't leave you underwhelmed. For a little bit more money, you could start to build a new separates system around your existing Tannoy speakers.