Hi guys, recently bought a Focus from a local garage. It is still under warranty, so should get everything done free of charge, but I would like to know what the problems could possibly be. Have had a few issues which have developed over the past few weeks -

Firstly - I cannot get the car's headlight's on properly. Occasionaly they will work, but tonight I had to drive 90 miles with them on dim as everytime I tried to put on the headlights, full beams came on. I mucked around with the switches and tried them in every position they could go in but nothing would change it
Secondly - the car keeps losing acceleration and becomes jumpy - I did wonder if this could be related to the fuel pump or spark plugs, but tonight as I was mucking around with the headlights, everytime the full beam lights came on it sounded like the engine might conk out - so im wondering if it could now be battery related -
Thirdly - I doubt if it is related, but the central locking on the drivers side is a bit temperamental and only works about 90% of the time.

I did wonder if all of this could be related. I thought a focus would be a good investment, ford's have never been a problem for me in the past as I have had a Fiesta and now the other half has a Ka. Any suggestions woulf be greatly appreciated.