Hello James,
Since you are not doing anything illegal, there is nothing to fear of. You are simply accepting a tech outsourcing project so taking payment in bitcoin shouldn't be the problem at all as long as you are paying tax on the income.
Since, you are receiving $6K per month, you will be covered both under income tax act as well as GST Act. Hence, you have to pay GST on services as well. Get GST number asap and deposit tax periodically after consulting with a CA.
I have a question for you, what is the legal status of your startup? Have you registered it as a company? If not, then you can't open corporate account on Zebpay or Giottus. Corporate accounts are only available for companies. If you have unregistered firm then it's better if you make an individual account on Zebpay (or any other exchange), sell your bitcoin proceeds on exchange, receive INR in your bank account, show INR receipts as your income, pay salaries out of your bank account, show salaries as your expense and pay income tax on net proceeds as business income.
And no need to worry about showing source of income. Just get a contract signed by you and the UK party detailing total project duration, total money receivable, fact that money will be received in bitcoin, etc.. Also regularly issue invoice to the UK Party. These all would be enough in case authorities inquire about your business.
Thank you webtricks for our reply,
We are incorporated entity LLP, we can register as a corporate account in zebpay, i spoke with them they are ok with that , but my question is as client is not giving us an agreement , how can we prove that we got that bitcoins from another company and can raise invoice for that and pa tax , My CA is sating we need to show legal documents that we are working for that client and raise invoice for him to pay the tax .