I think there are Labour MPs that have principles but are moderates.
Its possible to be moderate labour without being a Blairite
Chuka Umunna wrote:
New Labour left the country a much better place to live in. Even David Cameron accepted this. Three Labour governments was an extraordinary achievement and down to the hard work and commitment of thousands of party members. But its success was limited by the failure of Third Way politics to challenge the power of capital. New Labour failed to challenge sufficiently the neo-liberal market order of Margaret Thatcher. It did not do enough to reform Britain’s economic model to deliver better outcomes for people in all parts of the country. It failed to rebalance an economy over-reliant on the financial services sector in the South. It did not take the action required to dampen bubbles in the property market, nor to redress the lack of savings, nor to act against the rise in household debt.
Full essay here:
https://www.newstatesman.com/politics/uk/2017/03/chuka-umunna-labour-alternative
many would consider Chuka Umunna to not represent Corbyns socialist vision and therefore a Blairite.