I've done the moneyhelper calculator and it says I'm all good now at 50% of my current income, without adding any contributions. Congratulations hippy, you have passed pension pot pissing 101.
As in your existing SIPP and pension pot are already big enough to fund half your current income? Smashed it, well done! I'd be trying to retire before 55 if I was in that position...
If you actually do all of that, you've basically sorted it for the rest of your life, so at that point you can completely forget about it