Bottom bracket question

Hi all,

Just a quick question from someone who cycles regularly but knows nothing about the mechanics of a bike!

I've got an old warhorse of a Land Rover hybrid and have done 1,500 to 2,500 miles in the last couple of years as I've gradually got more into cycling. Last year I took it to my local independent cycle shop as the gearing was having a struggle (apparently not helped by having 18 gears and only using 3 or 4!) and a creaking noise coming from the pedals.

They changed the cassette and chain and also the bottom bracket as they said there was excessive play. Everything was ok for a while although the creaking came back intermittently after about 6 months. Now nearly a year on and after 8-10 miles the creaking starts again and gradually gets louder the longer I cycle. I have a 55 mile charity ride in two weeks time so don't really want to screech around the course or it to fall apart mid ride!

Would the bottom bracket have gone again in this short space of time (I've done around 1,200 miles on the road since the change)? Could there be another problem? I've done a bit of research on bottom brackets and it doesn't seem to be a part that fails too often.

I'm planning on finally getting a new bike next year so don't really want to go to the expense of investigation costs and changing more parts on a bike which only cost me £180 six years ago!

Any help you could give would be gratefully received!

Cheers
Dave