Can anyone good with cars help!?

Basically my vauxhall corsa 1.2(52 plate) Has a ticking noise coming from the engine which is unusual it comes and goes which I find odd, I've heard two things either the timing belt has gone or the oil needs changing because of the tippets or something. I had the timing belt changed this time last year, well thats what the guy said in the garage he changed! And I haven't had a service since I've had it. I do check my water and oil regularly and there is always enough, sometimes some of the water goes though. I would be truly greatful if someone could tell me what they think it is!?