Denafrips offer to replace my faulty Pontus 15th, for a replacement fee?

My Pontus 15th has developed an issue with the right channel output so I reached out to Denafrips to hopefully get it sent to be looked at/fixed (still under warranty)

However, they don’t have anyone here in the UK to look at it; instead they’ve offered to replace my current Pontus with a brand new replacement for a replacement fee of 400 USD but free shipping.

I would have to pay for shipping my Pontus, back to China which I don’t have a problem with.

I can’t decide in my mind whether this is a good offer or not, considering my Pontus is just over a year old and within warranty.

On the one hand, I can see this is as a decent compromise by Denafrips and a show of good will, as they will send me a new unit without verification of the fault, but on the other hand, is the replacement fee a little unreasonable considering the circumstances/the issue with my unit, and valid warranty?

I’m unsure if I’m honest; if I’d recently bought the unit and were sending it back because I didn’t like it, I’d understand a fee, but returning due to a fault, I’m having difficulty coming to terms with the fee.

Is this a generous offer and I’m being unreasonable, or is the fee unreasonable?