Claiming tax relief dental

I am self employed jointly assessed with my husband PAYE worker and will be paying the remainder of tax due for 2007 in October. I need expensive dental treatment done which can be offset against tax relief but do I have to wait until 2009 to claim the tax back when I submit my accounts for 2008 or can I put this through this year?

Also my income is only taxed at 20% but as we are jointly assessed does this mean I will get 42% relief?

If you get the dental treatment in 2008 then you can offset it in your preliminary calculations for 2008 as far as I know. If you are jointly assessed, presumably you are not paying tax at 20% for all your joint income and you can offset your dental costs against your (pl) higher rate of tax.

Sprite

If the work is paid for in 2008 then it is when you submit the return for 2008 that the relief will be granted. It will be granted against the highest rate of tax first on your joint assessment. You could try and factor in the likely effect of this on the overall 2008 amount when paying PT but you still must make sure that this is not less than 90% of the ultimate 2008 liability. If this is difficult then the 100% rule would usually be safest.