Hi.Assuming that you are considering making the SEIS investment in the current tax year, 2013/14, that your large income tax liability was for the 2012/13 tax year and that the small income tax liability will be for the 2013/14 tax year you can elect to have part or all of your investment treated as having been made in the tax year prior to the actual tax year in which the SEIS shares were acquired if that is beneficial to you. Take a look here for more on that.I'm afraid that it is not possible to backdate a capital gain from the current tax year to the previous tax year.I'm sorry this is probably not what you wanted to read but let me know if you have any further questions.
Thanks for your swift reply. One of the capital gains this year will be from the sale of a sculpture. I also have a loan from my wife which has a similar value to the sculpture. If the sculpture was transferred to my wife in the last tax year to pay off the loan would this generate a capital gain for me, or does this get caught up in the no capital gains or losses between spouses who live together?