No. The expenses incurred in setting up your self employment business, can only be set against the turnover from the self employment business, once the business has started trading.
BIM46351 advises that certain cost incurred in setting up the business can be set against the trading income, once the business commences trading, providing they meet the 'wholly and exclusively' test.
You can find more here:
BIM46351 - Specific deductions: pre-trading expenditure: scope
Additional guidance on expenses and the self employed can be found here:
Expenses if you're self-employed