Here are two activities on the Spring Statement for your A-Level Economists. The first looks at the economic context of the statement and how this may have influenced the statement. The second looks at the impact on different groups in society. Since I made them with a cover lesson in mind, they (should be!) fairly self-explanatory, so they would probably work just fine for homework too.
For more ideas, take a look at these posts (1, 2 and 3) about the Budget - many of the activities are easily adaptable to fit the Spring Statement.