This is just my view and I'm not a financial advisor but I'd go for the lower 3.23% variable rate.
Lower repayments now should be advantageous given your partner's current difficulties.
And what people often forget is that to "profit" from fixing in circumstances such as yours, the average variable rate over that 3 years needs to be greater than 4.7%. In other words, you're almost trying to outwit the bank. I know plenty of people who've fixed their mortgage but I only know one person who "profited" from doing so. And given the inflexibility of such mortgages (i.e. what happens if you want/need to sell?), it probably wasn't worth fixing at all.
If you're happy to meet the fixed repayments, why not save the c. €320 difference every month?