It doesn't look like you need anything too complex.
I notice you've split your finances and his above. However, looking at what's best for the total family picture. There might be reasons you treat your finances separately.
Assuming husband remains PAYE:
You talk about savings for retirement, but you're using your current account! Use a pension, and get tax relief.
You're putting in 1560 a year which won't make much difference to you in retirement. I would calculate the maximum you can contribute (between you) at the higher tax rate, and put that much in. If you've an amount that will be matched by employer, make sure it's at least that much. Work out between you who's pension gets funded, and by how much. You can still make contributions for 2019 and claim tax relief.
Calculate how much money you need to keep for rainy day, and planned expenses (like the college fund). Put that aside into a separate current account so you're not tempted to spend it!
Pay everything else off your mortgage.
You say you want more comprehensive life cover. I don't think you need it. Relatively small mortgage. I assume you have 4 times salary cover at work? It's worth digging out the details. What might be worth considering is income protection in case one if you can't work, but the amount you can get is limited by your salary. They won't be expensive, and are tax deductible.
Re farm partnership - you need to be talking to a good tax planner familiar with farming, particular inheritance / retirement reliefs, so both your husband and his father's situation are taken into account. Ask around in the farming community - there's usually 1 or 2 go-to people for this type of thing.