What documents do I need for English language – I’m confused

[Wakeuphappy]

I got a MEng degree from a UK university, it is recognised on UKBA PBS. I then did LIUK test a few years back and used the pass certificate to obtain ILR (from 5 year working). I have been working for 6 years for a well known company.
My questions are:
1. Do I still need to do ESOL English?
2. Is it enough to just submit the LIUK pass certificate and degree certificate?
3. Do I have to get a letter from the English university to state the degree was taught in English?
4. Over the years I have submitted a lot of pay slips, bank statements, p60s to obtain work permit, Tier 1 visas and ILR, do I need to submit all the documents (PBS print out) again for citizenship application?

[Amber]

The degree certificate and LIUK certificate should suffice KoLL.