Advice needed for securing a refund for a L502x that can no longer boot, Two Weeks OLD.

I purchased a L501x originally, had severer overheating problems, after several failed call out by technicians where they failed to show or inform me that they wouldn't I received a replacement laptop. This machine had the same issues, high temperatures and random shut downs.
Dell refused to do anything in regards to this replacement as I felt I was entitled to an upgrade on some level considering the period of time I spent dealing with this not to mention the several days I had to take off work expecting a technician. After much debate and threats of the UK Standad Tradings act I received a full refund. With this refund I was able to purchase a L502x of higher specifiation than the replacement I was seeking for the faulty replacement.
This new L502x is now failing to boot in any sense.
Rather than look for advise on how to remedy this I will be seeking a full refund and purchasing a Desktop as despite the inconviene of limited portability I will be able to get a higher specification machine and won't have to deal with Dell anymore. The laptop arrived approximately 2 weeks ago. Outside of the standard return period however as I am not looking to return due to a change or heart but because I have recieved a faulty product under UK law I am entited to a full refund.
Dell aren't so sure.
I spoke to an XPS manager today although the best he could offer was an engineer visit on Tuesday rather than organising a refund. I'll be receiving a call back tomorrow from his superior who has the power to authorise refunds and I'm looking for advise to help me procure this.
This new laptop is under a seperate customer than the first as things didn't end plutonically after the last couple of issues.
I have been polite and stating I know my rights however the person I spoke to today reiterated the company policy. When I stated the law takes precencde over corporation policy he remained silent.
Does anyone have any tips to ensure I receive a full refund on a laptop that is 2 weeks old, already failing boot in any sense and had intermitent shut downhs. I also mentioned the deception made when ordering; i.e I was guaranteed it would be a 15day delivery and ultimately was comfortably twice that.
I'm aware ranting and raving at the customer team won't help but I'm sure there are certain "buttons to press" to ensure I'm not stuck with an a laptop I'm not sure I can ever be content again with.
This has been the final straw for me with Dell, and to be honest it's a real shame as they are incredibly competitive pricewise.
So any advice is HUGELY appreciated as I know their underhanded tactics!

 

I guess it depends on why it wont boot (rickered Windows vs failing POST, for example) but according to the link below 4 weeks is reasonable for a refund if something is bad, under the consumer credit act

Consumer Rights: "Give me my money back!"...

It's a nice laptop - even though you're annoyed wouldn't it be worth letting Dell try to fix it? If they can't, or something else goes wrong after an engineer visit, I'd think you'd have a great case for a refund!

 

Get your refund man, don't accept a tech coming out.
My XPS 15 failed to boot during midterms, and it took them a MONTH to get it fully repaired, and this was with on-site next day warranty upgrade as well.
Save yourself the headache.

 

After an escalated phonecall I was told the best they could offer was a tech visit and then if I was in anyway unsatisfied afterwards I can claim a full refund. It seems it will add a day of two delay to my refund but it also means hopefully I have more time to search for bargains.
This seems easy enough and I have requested this in writing and will be giving a close read.
I'll still be getting my refund one way or another.

zygotic I agree it is a great laptop although I'm tired of the faults and want the flexibility of having a desktop. I enjoy tinkering too much and there isn't the scope playing with the hardware in the same way.

I'm going to be selling a variety of laptop related peripherals including a charger, 8GB DDR 1333mhz RAM and an internal blu-ray burner.
Anyway interested hit me up, if not I'll stick them on eBay