Is she putting the money away herself or is an employment related one that her employer also contributes to?
If she’s doing it herself, then she should do a tax return to get the tax relief on it as pension contributions are deducted before tax is calculated. Employer related pensions are great in that often up to a certain % they’ll match your contribution, thus doubling your investment before you’ve even started.
Personally I’m currently using Hargreaves Lansdown and they’ve been pretty good so far, but then they’re just a wrapper for investing in other people’s funds. I also like their active savings which mean I can have savings products with other institutions through them too, thus making shopping around for the best rates a doddle.
It’s up to her what she does with her spare cash, there’s no harm locking it away for retirement now as it’ll have the most time to grow. If she’s thinking it’d be useful when she’s back from travelling then a fixed term high interest saving product may be a fair idea, or even a Stocks & Shares ISA.