Your business year end, not 5 April, is relevant for capital allowances purposes.
If, however you are running a business and making up accounts to 31 March or 5 April you should consider buying plant and machinery to take advantage of the £1 million Annual Investment Allowance (AIA).
The AIA provides a 100% tax write off for new and second hand equipment used in your business. This tax relief extends to fixtures and fittings within business premises such as electrical, water and heating systems. AIA does not apply to motor cars but there is a special 100% tax relief if you buy a new zero-emissions motor car.
If you are running a limited company, remember that new plant and equipment currently qualifies for a 130% tax deduction.