Im wanting to lose fat and build some muscle mass before going back into rugby training and ive been considering using protein shakes and creatine in order to do this. Is it possible, however, to lose fat whilst building muscle mass throguh using protein shakes and creatine?

I dont want to find that im just putting on more fat through using these.

to lose weight, you need to reduce calorie intake
to gain lean muscle mass, you need extra calories

see the paradox?

newcomers to exercise can manage to do both for a few months, but then the body adapts, and they need to choose fat loss, or lean mass gain, and focus on that goal for a while, then switch. bulk, cut, bulk, cut...its cyclic.

you'll only put on fat if the protein shake pushes your daily calorie intake above what you need.

In that case it may be an idea to replace a lunch meal with a protein shake in order to make sure i dont push my calories over the daily 'allowance'.

One protein shake, or replacing a meal with a protein shake isn't gonna do much of anything at all. Decide what you want to do and go from there accordingly. By that I mean you need to know exactly what you want, plan out a diet, and stick to a exercise routine.