What’s the best way to sort a knock like this… 
I’ve bashed it back into shape as best I can… 
Plenty of filler still needed.
Any advice/tips as to what to do and how best to do it!! Cheers 
Unless you have had done anything like this before, you are going to need a professional. It is relatively easy to wet & dry the surrounding area of the damage then fill the damage in with filler and then shape it back to it’s original shape.
Obviously the rear light will need to be removed first. The big problem with Classic Red on that age of car is getting the paint to match as your car paint will, like mine, will have faded.
Usually the whole panel needs repainting but, even then it will show up a brighter red than the adjacent panels. To only repaint the damaged area takes a good paint sprayer to do.
I had some deep scratches on my car when I bought it and I filled them in and spray painted over it after filling and sanding it level with the surrounding area and after compounding and polishing it, it stood out like a sore thumd as the colour was so much brighter than the original paintwork. I got round it by respraying the whole car eventually.