Funding for Grange is renewed on an annual basis for each financial year (April to March). So as last year's grant is about to expire, it would appear that now is when they need to apply for the next funding. According the (as yet unverified) source, the team have applied for a 6 month extension only, to continue their activities up to September.
Hypothetically, if the Met are under the impression from their German counterparts that CB is going to be charged within the next few months, such a move would be consistent with that IMO. Why would you apply for a full year's funding if you are expecting a charge in the case way before then? Conversely, if you think you have no more decent leads and that the German investigation is all but dead for you to assist them with, why apply for additional funding at all?
I just think the sceptics might want to curb any premature celebrations, this move might not signify what you hope it does.