Whether it is subject customs duty and VAT?

I hope someone could give me clear guidance. I placed an order in Flannels online store from Netherlands and I collected it in the store in London. Unfortunately, I want to return the goods (approximately 1000Euro) now and I need to send the parcel to London from Amsterdam. I get the return label from Flannels and I will ask DPD to ship it. I would like to know whether I would pay customs duty and VAT for this returned goods in UK? Thanks in advance.

Hi,
You can get a relief if you’re re-importing goods into the UK that have previously been exported or transported from the UK.
This is known as Returned Goods Relief.
Please write ‘Returned goods — relief claimed’ clearly on the package and its accompanying import declaration.
The declaration must include a complete and accurate description of the goods, including their quantity and value.
If you’re registered for VAT, make sure your VAT number is quoted on the declaration (CN 22 or CN23).
More information on below link:
Pay less import duty and VAT when re-importing goods to the UK
Thankyou