Rear light lens replacement

My rear light lenses are both a bit cracked, especially around the screws. I've not been happy with them since I bought the dandy but the cost of replacement, if you can find one, is normally pretty high and entails buying the complete unit. Then I saw these

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They seem to be the same size and shape so at £11.30 for a pair I thought I'd give it a go I will report back in a week or so.