On Vanguard i believe there’s a threshold arounf £375/ year after which you dont pay anymore fees and thus as a % your fees will go down. I have funds with both, but I have stopped adding to FT since ive seen it appears to be relatively costly to get the funds out. I think everyone has assumed that FT will fixthis over time as FT get to be a more mature business, but thats not guaranteed. So in the meantime im paying into my Vanguard pension.
Also and quite important it depends if you are happy in funds and being relatively inactive, or do you back yourself to trade shares , I think Vanguard is a set and forget strategy and FT is if you want to be more active and back yourself and your decision making versus a passive index. Good luck 