It is kind of important for proofreaders to be accurate. What does 'delete multiple spaces within words' mean. Generally spaces go between words and that is how we know where one word stops and the next one begins.
In all the following steps, pay careful attention to the spaces between the "quote" marks. Note the last one won't catch instances where the 'empty' paragraph actually contains a space or a tab. You might want another couple of replaces to fix them first.

1. Find "[ ]{2,}"
Replace " "
Wildcards ON

2. Find " ([,.:;]{1})"
Replace "\1"
Wildcards ON

3. Find "^p^p"
Replace "^p"
Wildcards OFF

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Andrew Lockton
Chrysalis Design, Melbourne Australia