How to protect my redundancy and re-hire

Apologies for treading old ground
My wife is made redundant leaving next week having worked her full notice period.
Today she was asked if she would come back for 6 months on a contract basis
Clearly she wants to protect the redundancy payout (a lot less than £30k). She could contract via my limited company in the same service sector.
So, does going back via my company protect her from the long reach of HMRC?
Would a gap between leaving and restarting make that more acceptable?
Would restarting the next day be acceptable if the contract is dated say 6 weeks after leaving and invoicing for work carried out only after that 'gap' despite actually continuing straight after actually leaving?
Hope that makes sense!
Many thanks for your thoughts