I’ve got the same problem. Same holding across different brokers. The only way I’ve easily been able to discriminate is to mouse over the attachments in the individual equity to see which broker the buy/sell went through (because I forward the confirmations to Sharesight). Helps on Buy/Sell but doesn’t solve DRP and doesn’t give a consolidated view.
I agree that it would be great to be able to see the chess sponsorship broken down within each holding. I have the same problem when automated dividends are issued. I end up needing to delete them and manually recreate for each CHESS sponsorship.
The other weakness here is that the Xero syncronisation can only sync to one brokerage account per portfolio as well.