Problems With Dell Laptop

Hi I will keep this as brief as possible in the hope that someone might be able to help me.

In April of this year I bought a laptop from Dell. All was fine until September when the hinges holding up the screen failed. I phoned Dell support, and in fairness to them the sent out a tech guy to replace the screen. I was happy with the repair and all seemed well.

In November the hinges failed again(a quick Google search showed this to be a very common fault with this model of laptop).Coupled with this the baseplate had warped and pulled away from the laptop. Again I rang Dell support and despite my request for a replacement laptop, it was eventually agreed that they would take the laptop into the service center as they could not be sure that the problem wasn't "customer damage".

To cut a long story short the laptop was returned to me this morning with the hinges and the baseplate replaced, however it was missing a part and the lighting system is now not working. having rang Dell yet again they are still talking repairs.

I am furious at this stage as it was not a cheap laptop.

My question is am i legally entitled to a replacement
/refund at this stage or do i have to let them keep fixing it?

I think it if it keeps failing with the same fault you could ask for a replacement of a different model. They can't keep fixing it, till the warranty runs out. Though I don't think theres a specific number of times.