Conington are very helpful and friendly Landing was around £10 but check by phone.
Taxi will be around £10-15 into Peterborough. Last time I got one to a hotel on the West side of Peterborough it was £10 but check first as they sometimes have a 'special rate' and I got charged £15 for the return journey.
Not sure how Conington compares to Sibson for distance.