Help with letter to neighbour about kitten

[Alakazam7]

I posted on here a few weeks ago about my kitten no longer using the litter tray. I have now found out where he is going as a neighbour who I have never met before came to my house this afternoon to complain about my cat using her garden as a toilet. I was shocked and flustered so said I'll keep him in the house.
I understand her concerns but don't feel happy keeping him in all the time as he loves being outside.
I have bought a card and was thinking of a message similar to the following.
Dear Neighbour (I don't know her name)
I am sorry that my kitten has been using your garden

Posted too soon will continue

and wouldn't want to cause your enjoyment of your garden to be spoiled at all.
However my kitten is an active cat, still growing and needs to spend some time outside each day. He loves playing in the garden.
Already I keep him in every night and he has a litter tray inside and outside.
I would like to try to find a solution that would suit us both so would like to offer to pick up any mess and will buy some cat deterrent spray for you to use in your garden.
I apologise again for the inconvenience and thank you for informing me of this matter.
Regards

Will this letter just make things worse or is it likely to have the desired effect? (Sorry for the numbers of posts this has taken, trouble with phone!)

TBH....cats poo in gardens. It's a fact of life. There's not much you can do to stop them.

If you offer to pick up mess, you'll likely find yourself being called round every day to do it - forever! Bear in mind it may not just be your cat using that garden as well.

I'd buy the deterrent spray and pop it round, in the interests of neighbourly relations, but I wouldn't worry about it after that.

Thanks I'll do that tomorrow and hopefully that will be enough then. I can't keep him in forever, he so loves going outside.

Cat proof your garden. Sorted.

No don't offer to pick it up. Buy her a water gun and tell her to use it and leave it at that.

Thanks, I will provide repellent spray and advice about a water gun, orange peel etc. After that it seems like it is up to her to sort it out. I feel like I'm doing all I can but won't keep my adventurous boy inside all the time.

Don't write a letter and definitely don't offer to pick it up - it's a fact of life, cats poo in gardens. I'm sure your cat isn't the only cat in the neighbourhood so if it isn't yours, some other cat will be along soon.

Just say you're very happy for her to spray it with water with a water pistol or shoo it away but you won't be keeping it indoors just as most catowners in the UK don't.

My parents have had complaints about their cat so they have given the neighbour a water spray if he sees him. However there are at least 6 other local cats so they don't feel entirely to blame.