I think it will generally be busy throughout the Easter holidays. Easter Sunday and Easter Monday might be a bit quieter because of the MAP restrictions. The worst week will probably be the middle week leading up to Good Friday (14th April to 18th April) as all schools are off that week. That means the best time to go would be the week beginning the 7th April or the week beginning 21st April avoiding the week when there is overlapping school holidays. The local schools all have the second 2 weeks off which would mean that the week beginning 7th April will probably be the quietest, if you can go that week.