Last month the Tax Office wrote to me saying I would no longer receive tax credits, but I did nothing about it. Now my wife is expecting another baby so has reduced her working hours. Can I get my tax credits back?

A. You need to make a new tax credits claim as soon as possible, don't wait until the new baby arrives. Your reduced family income may mean that you qualify for working and child tax credits already, and if you don't, you will at least have submitted a protective claim for 2012/13. Under the new rules, from 6 April 2012 couples with children must work at least 24 hours per week between them, and one member of the couple must work at least 16 hours per week. There are exceptions if one person is disabled, incapacitated or a carer.

My business is VAT registered but the sales have dropped back, so my turnover is less than £75,000 per year. Can I stop charging VAT on my sales?

A. You must not stop charging VAT until you are given permission to do so by the VAT office. You need to apply to deregister for VAT on form VAT7, and send the completed form to the VAT deregistration office in Grimsby. You must continue to charge VAT on your sales until your application to deregister from VAT is accepted, and this has been confirmed by the VAT office.

I'm thinking of starting a new company. Will it qualify for the NIC exemption?

It depends where your business is based. Businesses in the east and south-east of England, or London, don't qualify for the so-called NIC holiday. The south-east region stretches all the way up to the Northamptonshire border, so you need to be quite clear where your principal place of business is. Secondly it must be a new business, not an existing business that has been transferred to a new company. There are also some excluded sectors such as road freight, coal and export businesses. We need to talk through the detailed rules before you apply for the NIC holiday.

I am about to relocate abroad. Can I continue to contribute to my tax-free ISAs in the UK?

Q. I am about to move abroad, for what I hope will be a permanent relocation. Can I continue to contribute to my tax-free ISAs in the UK?

A. To open an ISA you must be resident and ordinarily resident in the UK for tax purposes. This broadly means that you normally live in the UK. There are exceptions for members of the military and government employees who are sent to work abroad. Once you have emigrated, you will not be permitted to open a new ISA, or contribute to ISAs already held. Also the interest paid on the ISAs you already hold may be taxable in the country you live in.

Can a company deduct the cost of private medical insurance for employees from its profits? Is there a tax charge on employees who receive insurance?

Q. If a company pays for private medical insurance for its employees and the contract is between the employer and the insurance company, is there a tax charge on the employees? Can the company deduct the cost of the insurance from its profits?

A. Where the employees earn £8,500 or more a year, or are directors, there is a tax charge for the individuals based on the cost to the company of the insurance. There are exceptions to this tax charge for eye-tests required by health and safety legislation, annual medical checks or health screenings. The company can deduct the cost of the insurance from its profits, as it is part of the cost of employing staff.

I have never declared income from an investment property, or paid tax on it. How do I go about putting this right?

Q. I bought an investment property about 6 years ago and after expenses I have a surplus of about £250 per month. I have never declared this income or paid tax on it. How do I go about putting this right?

A. The Taxman is running a series of campaigns to encourage people to come clean about unpaid tax, the latest of which is aimed at people who sell through online markets. Although this is not your situation, you can make a disclosure of your rental profits. You will have to work out how much tax you owe and the interest due on that late paid tax, but we can help you with this. There will also be a penalty to pay, but as you are volunteering the information without being asked, the penalty should be minimal. The penalty could possibly be about 10% of the tax due.

All my income is taxed under PAYE, so surely I don't need to complete a tax form, do I?

Q. I've received a £100 fine for not submitting my tax return, but I don't remember receiving a form to complete. All my income is taxed under PAYE, so surely I don't need to complete a tax form, do I?

A. You should first ring the Self Assessment helpline on 0845 900 0444. Have to hand your NI number and your unique taxpayer reference number (UTR), if you know it. The Tax Officer will confirm whether you need to complete a tax return for the year to 5 April 2011 or not. If you do need to complete a tax return for that year you should do that online, if you submit a paper form now you will receive an even higher penalty. We can help you submit your return online, if one is due.