EIS carry back, Income Tax relief

A qualifying investment is made in the first 6 months of 2005-06 tax year, and it is desired to elect for 50% of it to be treated as if paid in 2004-05 for the purposes of claiming IT relief.

Box 15.4 seems to give no option to divide a total pay between amount for current year and amount related back, but the tax calculation for current year is based on this box so we assume that the entry in this box is net of amounts related back.

Full details of the claim and amounts related back are included in the white space, but if we complete box 18.5 with the taxation effect of the carry back then it fails online validation on the grounds that there has been no carry back of losses or of pension contributions nor farmers averaging. It does not seem to recognise that a carry back of EIS relief is available.

Does this sound right?
Clint Westwood