Would you consider adopting a new feline friend for her (and you) ?

It sounds like Lucy needs a new sibling, not a replacement for Gigi but another cat for you and Lucy to love.

The reason she bothers you at night, is cats are very active at night playing/hunting. She probually misses Gigi more at night than at other times.

If you are not ready for a new furbaby, I would give her as much attention as you can. Play with a laser pointer to get her tired out and move the scratching post to where she is scratching.

BTW to those places she scratches smell of Gigi ? As scratching is part of the scenting behaviour.

{{{hugs}}} to you and Lucy.

PS. Where about in England do you live ? (County)