There's only a paltry bonus of 4k for the £450 Plat card. Better to wait for a better bonus.

More reasonable is the 22k bonus for the free (for first year) Gold card. PM me if you'd like a referral for that instead. If you have another-half, you can then refer them for a plat when the offer improves (if ever).

Your bmi card should reissue without issue. BA and mbna are continuing the card as it works for both sides.