Thanks for your input. How can I tell if the file is corrupted and if it is how should I proceed? 

I've tried various combos of likely mistypes but there are quite a few different password combos it could be so here we are. Yet to try brute force as it's the nuclear option due to the % that is taken. I'd not seen the do it yourself version before so I'll give it a go.

The thing I find most strange is that when trying to view my seed phrase via inputting the pw all others give me an invalid pw message while one very logical option specific to me actually takes me to a blank seed window. I checked my electrum raw data and I do indeed have an encrypted seed. I tried that particular pw when trying to import the private key and got the invalid pw message.

Followed this advice and got the invalid pw of doom. It seems the previous 'success' of viewing a blank seed window was a false positive, cheers guys.

Hey guys, have some lost funds from 2013 which I've sporadically tried to regain access to over the years always getting an incorrect pw message. Well the other day when attempting to see my lost seed the pw was accepted but the seed window was blank. As it's such an old version and is offline I was wondering whether that was the cause of the blank window or is it possible I never created a seed? I've saved a copy of the wallet but I'm still hesitant to upgrade before getting some further advice on how to proceed.

I also tried following the advice in https://bitcointalk.org/index.php?topic=553096.0 but as it's from 2014 I'd expect it's also based on electrum being online.

Any advice would be greatly appreciated, thanks in advance.