Based on your advice to date and what I've otherwise read/guessed, this should be the sequence of steps:
1. Back up old wallet folder
2. Back up old consensus folder
3. Download and install the new client
4. Open the new client and create new wallet (I'm assuming the same thing will happen on opening 0.5.2 as did for 0.5.1 – i.e. automatic generation of a new password/wallet)
5. Close the client
6. Replace the new wallet folder with the old wallet folder
7. Replace the new consensus folder with the old consensus folder
8. Open the new client again and old balance from previous wallet will appear.
Is that correct?
Thanks for your further help
Yes, except you can skip step 4. since you're copying over the old wallet no need to create one just to throw it away