Purifying a linear plasmid after restriction digest?
Can't exactly say what problem you are facing but you can follow these steps for efficient restriction digestion and elution.


Never set up a digestion reaction with more than 1µg DNA per 20µl; if you require more digested DNA, then set up multiple 20µl reactions with maximum of 1µg DNA in each (500-700ng is ideal).
10µl enzyme for a 230µl reaction: bad idea. Set up 10×20µl reactions with not more than 0.5µl enzyme per reaction tube. 
Avoid overnight incubations; 4 hours should be sufficient (NEB PmeI is 10 units/µl and 1 unit is the amount required to cleave 1µg DNA in 1h in a 50µl reaction. You are adding 5 units in 20µl. Overnight incubation is too much)
Deactivate the enzyme after the reaction.
Just run a little bit of sample from one tube in the gel to see if digestion has happened. After confirming digestion simply use the PCR purification kit. You can pool your tubes. 
Optional: Elute in Tris-Cl pH 7.5 instead of water or use warm (60⁰C) water.