Whether or not you take out a maintenance package, you must service the vehicle as per the recommended manufacturer guidelines. You can find this information in the vehicle handbook or digitally.
It's also important to ensure any repairs carried out are in accordance with your leasing agreement. For example, some contracts stipulate original manufacturer parts must be used, and authorised service centres must carry out the work.
MOTs are not required for the first three years, but leases over this time frame will require an MOT every year after that.
If you have any questions about managing your lease vehicle's maintenance, contact your account manager, who'll be happy to help.