It was quite a while ago that we did our research into consumer law, and we did it by contacting them by telephone. We've had another look and we don't seem to find much specific information of what is available after the 6 month period has passed. We managed to ascertain the following:
"141. After the first 6 months, the trader may apply a deduction to the refund to account for the use that the consumer has had."
This can be found here:
http://www.legislation.gov.uk/ukpga/2015/15/notes/division/3
So essentially we have the right to deduct an unspecified amount to cover the time that you used the product without issue. Also, we have the right to demand that you prove that the fault was not caused by yourself, essentially you'd need Eufy to confirm in writing that your product faulty through no fault of your own. You can find this information here:
https://www.gov.uk/accepting-returns-and-giving-refunds
Due to all of the above, I feel that allowing you to use 100% of the funds on an alternative product is actually more than what we're required to offer. If you don't wish to take us up on this offer, we can offer you a further two options:
1) Return the item for a partial refund of 50%(GBP 79.99).
2) Keep the item for a partial refund of 20%(GBP 31.99).
Please let us know how you'd like to proceed.