Spinab,
If your options pack was a paid optional extra, it sadly won’t be refunded if you return the car. All you get back is the pro-rata AP. As someone above has said this is only refunded after you collect and pay the AP on your next car.
Motability may waive the £250 early termination fee on your BMW, however that is at their discretion.
I would be wary about having the BMW seats ‘re-trimmed’ though. You maybe just better obtaining a different vehicle that meets your needs. Then perhaps extending the lease on it so you have 5 years motoring in a much more suitable vehicle.
Mike