Nayls,
As usual with tax we're getting into complex areas which cannot be properly dealt with on a site such as this. However, I can tell you that taxabale employment income includes salaries, bonuses, allowances, perquisites and benefits-in-kind. Certain benefits are treated at preferential rates. For example, rent-free housing benefit (not cash housing) is normally calculated as the lesser of 10% of the assessable emoluments and the annual (rental) value of the property. By concession, only 20% of home leave passage is assessed on the expat employee. If in doubt, seek professional advice. I'm sure there are reputable local firms if the cost of one of the "Big 5" firms is prohibitive.