When you complete your self assessment form it normally asks you for the names of your business on more than one line, so you list on each line the names of your businesses. because you are a sole trader, and the profit goes to you personally, you are taxed on all your income together from each business that you run. If one business made a net profit of 50K and the other made a loss of 10K then you are taxed on 40K.
You can only reclaim business items. Personal health insurance, health club membership, are items which are your choice to have and nothing that perhaps your business requires. You can put down travel expenses on your accounts, and if you run your business from home. You can get business tariff electricity, phone bills, which can be offset.