DNGD

PAL

You don't say who built the guitar ! It doesn't look good based on the photos I would return the guitar. The nut looks awful
  and the string don't appear to have any break angle across the nut which is badly cut and this may be why your getting the  
  sitar sound .Also the work looks a bit shoddy. I would call this a faulty item and expect who ever you bought the guitar
  from to arrange and pay for the collection. Most good shops will do this. I'm not into naming and shaming but I feel you
  you should name the builder of this guitar and also show a full photo of the instrument in the hope that once the guitar has 
  been returned some other unsuspecting person possibly on the forum doesn't buy this guitar and experience the
  disappointment you have experienced. At the moment the dealer needs the opportunity to help you resolve the problem.
  I hope this helps.
  

gumbothewiddler

Looks like Ian Elson’s upped his game…

but seriously, return.

swiller

deffo straight back with anger at retailer. 
Looks like it was made in a late 80s high school woodwork class. Shane mgowans teeth for the nut.
All wrong, everything. 
Might be worth telling us what it is and where its from, so others dont make the same mistake.

BillDL

hollywoodrox said:

....... it is not meeting the requirements of an instrument of its price & stature .....

I agree with this.  The relevant part of the Consumer Rights Act 2015 regarding the "satisfactory quality" is here:

https://www.legislation.gov.uk/ukpga/2015/15/section/9

https://www.legislation.gov.uk/ukpga/2015/15/part/1/chapter/2/crossheading/what-statutory-rights-are-there-under-a-goods-contract

Note specifically that the price of an item can or should be taken into account when considering the quality.

The statute does stipulate the following to weed out really nit-picky claims:

"... if they meet the standard that a reasonable person would consider satisfactory ..."

but in your case it is a reasonable expectation by any reasonable person that an expensive guitar should not have been presented with the nut and the area around it in that shoddy and unfinished state.

Your right to reject and return an item as "unsatisfactory" is covered here, specifically under (3)(a), (b), and (c):

https://www.legislation.gov.uk/ukpga/2015/15/part/1/chapter/2/crossheading/what-remedies-are-there-if-statutory-rights-under-a-goods-contract-are-not-met