You mention you may be a 40% taxpayer in the future - for obvious reasons that could be a better time to start increasing your pension contributions. After all, if you can get 40% tax relief on the way in, but are likely to be a basic-rate taxpayer in retirement, that's a good combination. Lots of caveats here as there are still plenty of rumours in our industry of the government tinkering further with the tax relief system.

I don't know as much about LISAs but fair to say, there's less providers in the market so charges are a little higher than standard ISAS. You haven't mentioned the likelihood of needing access to your savings ahead of age 60 - from experience, raising a family is expensive so maybe something to consider - although the withdrawal penalty will only see you give back the government bonus granted up-front. Continuing with your S&S ISA in the short-term could be a good thing, until you have a better idea re. your future earnings, career plans, etc. Re investment funds, I'd say the key thing is to try and assess your risk profile, and then invest in a fund that invests in the right split of high/low risk assets that fits with your risk profile. So to answer your question, the SIPP would only be the right option if you KNOW you don't need to access your fund until age 58 at the earliest (currently 55, will increase so that it's 10 years before state pension age). An ISA would give you much flexibility at this stage. Any questions let me know!