So I talked with my husband, and we decided to go with Wise since it had the best overall rates. He had to call his bank to allow the transfer, since it was a larger sum, and so did it during his lunch while I was asleep (timezone difference).
I woke up to a transfer from OFX. He was very proud of himself for saving us £8 in fees, and was oblivious to the £50 loss in final total due to the worse exchange rate.
*sigh* At least it wasn't a bank, which probably would have been loss of a couple hundred £.