Cut the cream cheese into small blocks to help it melt faster, if you want to do this quickly put it in the microwave, 30 seconds per 250g to soften.
Whilst the cream cheese is softening, melt the butter slowly on a stove.
Once it is mostly melted add the crushed digestive biscuits.
Let the butter soak into the biscuits then pat down into your cake tin. Refrigerate.
Beat the cream cheese on a low speed until softened, slowly add sweetened condensed milk to avoid lumps forming.
Add double cream to the bowl, keep beating.
Juice the lemons then add the juice a bit at a time. For extra tang you can add lemon rind. It should be thick and creamy now.
Tip the mixture onto the base. Refrigerate for an hour.
Take out of fridge, check to make sure it has set, if not you can put it back in the fridge or put it in the freezer for ~15min as this helps it set quickly.
Evaluation: I I would mark it a 9/10. I think I could improve it by leaving it in the fridge longer because it was very soft when I took it out.