I need to remove spaces from disk numbers

I am looking to remove the space from a disk number (ie. abc123 - 6) however the file name does have to maintain spaces in the Track and artist info
so old file is:
abc123 - 06 - Jimmy Singer - Song1.mp3

new name should be:
abc123-06 - Jimmy Singer - Song1.mp3

Any ideas how I can use regular expressions for this?
I tried using REPLACE: (\d) - (\d)
WITH: (\d)-(\d)
reg exp: tick

but i keep getting this:
old: abc123 - 06 - Jimmy Singer - Song1.mp3
new: abc12\d-\d6 - Jimmy Singer - Song1.mp3

thanks in advance

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Reply to #1:
text to be replaced Replace: (^.+?)\s?\-\s?(.+)
Replace with: \1-\2

this expression should work with those variants:

abc123 - 06 - Jimmy Singer - Song1.mp3
abc123- 06 - Jimmy Singer - Song1.mp3
abc123 -06 - Jimmy Singer - Song1.mp3

and keep the final format

cheers

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