Regarding the formal diet, you need to be on the exclusion diet for 8 weeks before attempting to reintroduce foods. This takes about one year to do properly. You will still experience unexplained flare ups. I would not suggest attempting the fodmap diet in the UK without speaking to a nutritionist first. You will need a go referral.
The AMT is the excess of the tentative minimum tax over the regular tax. Thus, the AMT is owed only if the tentative minimum tax is greater than the regular tax. The tentative minimum tax is figured separately from the regular tax. In general, compute the tentative minimum tax by:
a JustAnswer user. Because of the AMT rules, you will need to calculate the depreciation two ways - Accelerated from normal tax and straight line for AMT calculation. Both numbers will pass down to your 1040 through the K-1. You will only need to worry about the AMT figure if your personal return is subject to the AMT, otherwise it is ignored.