Tier 2 Processing starts from?

So I'm mainly just looking for some reassuring (or worrying) comments I guess about your experience with this process, I'll list the details below.

I'm quite worried about my Identity Documents and about any possible correspondence not being delivered as my building has been having security issues, and royal mail posties haven't been able to access it sometimes.
I just wanted to ask if there's any kind of sequence to their work, I have been observing some of the posts and they seem a bit inconsistent.

I'm switching from Tier 4 to Tier 2 as a PhD student in his 3rd year of study. I'm sponsored by the University (a trusted sponsor + maintenance) and have provided my identity documents, sponsorship letter and university letter.

Do you receive any emails saying your application has been processed?
When do they send the identity documents back? Shortly after you apply or any time in the 8 week period?
Does DX get in touch by phone or email regarding the BRP?
Is there a reason for me to be worried now or should I wait till 8 weeks then panic?

Details:
Visa type: Switch Tier 4 - Tier 2, Standard Postal
Visa Submit/paid : 24 May, 2018
Biometrics+Posted: 25 May,2018
Received : Saturday 26 May, 2018
(28th of May was a bank holiday)
So far I'm past the 7 week mark, going through the 8th and I'm very worried that I may have missed postal correspondence due to the royal mail mess.

Any advice or experience you've been through would be appreciated.

Hello, I've applied and paid online for a switch to Tier 2 visa from Tier 4 on the 23rd of May. Haven't received any kind of acknowledgment letter except for the payment emails for the IHS and the Visa itself.
I got my biometrics letter instantly, I posted and did my biometrics on the 25th, the letter tracking says it was received on the 29th of May.

When do the 8 weeks wait start?

I'm having a bit of a panic because date of online submission means my 8 weeks ended yesterday the 19th of July. Date of Biometrics means it ends on Monday. And receipt of documents date means on Tuesday.

I'm working with a limited time frame as the funding for this job maybe withdrawn on the 6th of August and I need at least a response letter by then.