Discovery 2 Td5 oil in inlet

Noticed earlier in the week that my td5 had dropped from the max to below min of oil, (never normally uses oil) then this weekend found oil leaking from the hose between the inlet manifold and intercooler. I removed this hose to find a considerable amount of oil (I could pour it out) so checked the turbo and found minimal play and no trace of oil. Any ideas as to why the inlet would filling with oil yet not the turbo?
cheers