Nice analysis before the upcoming parliamentary elections. It is surprising that the most euro-sceptic deputy is member of the party that supports the goverment, which appears to be an EU-enthusiast. We can also observe some unusual behaviors (eg. some of the opposition members seems to be more pro-goverment), so I wonder if this analysis could be used for the prediction of deputy transfers between the parties.
I didn't put much thought into identifying the third axis. It may well be a linear combination of Euroscepticism and something else. The artefacts you see may be due to former transfers or to MPs who voted for part of the term only.