Opening a pension and then transferring immediately

OwnedByACat

I can get a cashback bonus if I transfer a pension. Is there a pension provider I could put £100 in and then immediately transfer? There'd have to be no exit fees. 

I already have accounts with PensionBee and Penfold but don't want to transfer those.

DRS1

Don't those cashback offers usually have tiers so the more you transfer the more cashback you get?  If so where do those tiers start - I imagine £100 might not even make it out of the starting gate. ii for example have a minimum of £10k.