Itās possible to transfer pensions, yes. If the investments arenāt on the Freetrade platform, youād have to sell the investment first and transfer the cash. I did this, and it worked well (coincidentally it was an Aegon Retiready pension).
BUT first you should check with Aegon whether your old pension has any āspecial featuresā. These might be bad things like chunky exit costs or good things like guaranteed future annuity rates if you stay with them. So you need to find out about those before you decide whether to transfer or not. More on the questions you might ask them here: MEGATHREAD: Freetrade SIPP - #24 by rod and if in any doubt speak to an independent financial advisor first.