Lawn Scarification
Over an autumn and winter its likely that some of the grass from the previous year has died back. This can be identified by the yellowness of your lawn in places. Also, as you have been doing other garden maintenance work over the winter you may have damaged the grass when moving loads of debris to the compost heap. This 'thatch' of dead should be removed to help healthy grass growth as soon as you can in the spring.
George uses a special Sisis scarfication machine to 'tease up' the dead from the Abbey House Gardens lawns. You can see from the photos that its methodical process that covers the complete lawn. Dont worry, you dont need to invest much money to scarify your own lawn... just use a stiff metal rake and a bit of elbow grease. Georges golden rule 'remember to keep your back straight when raking otherwise you'll only last 5 minutes.'