If you're planning a holiday, it's always a bonus to save some money. The costs can quickly mount up between flights, accommodation and of course, activities. However, there's a brilliant way to book your hotel that could save you hundreds. Hotels are often the most expensive part of a holiday, with UK travellers now spending around £92 per night on average for domestic overnight trips. If you're staying in a big city, that cost can soar even higher. Take London , for instance, where recent