Bmi Per Country Hand Baggage Measurement Restrictions BMI Baby?

Hand baggage measurement restrictions BMI Baby? - bmi per country

I fly with BMI Baby from Belfast to Manchester next week with hand luggage. Baby BMI measurements are 55x40x20. However, my bag measuring 56cm and 58 cm without wheels with wheels.
Do you think it's OK if I'm at the airport? Other measures are good and not more than 10 kg is permitted.