They do provide an income report for the tax year, I think it's a legal requirement for all providers to do it. However I have had a couple of cases (not with ii) where unusual forms of income weren't on the report, e.g. share distributions that counted as dividends.

No provider will give you a CGT report, it's far too complex and in general they don't have enough information, e.g. if you own the same investment with another platform. You should of course get contract notes for purchases and sales which is enough in simple cases.

I find that AJ Bell provide a good report for everything in their platform which includes
Income tax
CGT.
and the ERP

If however you have multiple platforms then obviously you need to marry the information and adjust for your own report to HMRC

You also need watch out for the 30 day reporting issue which a single platform on its own cannot identify, unless you sell and buy within 30 days on the AJB platform in which case their own CGT reports adjust the figures accordingly. Similarly they also take care of the Section 104 buys and sells automatically.

So for all the dealings and activity on AJB, I find their reporting pretty much covers everything for CGT. Even if you transfer In-specie and providing the ceding provider sends the information (which you need to ensure that they do), then they use the information to calculate the right CGT on a stock line.