Having the bov blocked is better than having it venting to atmosphere, but still not as good as having it plumbed back correctly. It can cause issues of running very rich when changing gears, and will actually be louder with it blocked (and make you sound like a wanker, trust me)
The bolt blocking the blue hose on the front of the engine is poor, you can get little caps to do it properly.
The breather system really needs to be sorted, but to do that properly means a new inlet pipe.
So its either keep the turbo on that manifold and get a new inlet made, and potentially have the manifold cracking, or get a stock manifold and pipework, fixing bov and breather and cracking manifold in one go.