Nothing at all mate, to save you the trouble I'll take the lot of your hands for a tenner.
But in all seriousness, the shirt I'd imagine would be worth a decent amount.
I've got a 98 home shirt signed by Richard Shaw and a load of other first team players and at the time I got it, maybe 5 years ago? .. it was worth around £150.
Judging by the price of the non signed shirts from that year I'm seeing for sale now, it could be worth more today.
Not an expert which is what you specifically asked for but thought I'd give my thoughts.
Certificate of authenticity makes signed items worth significantly more (or some other proof of signature). You can get them authenticated privately, but it's quite expensive normally. I had a 90's signed Roma ultras scarf that was probably worth £150+ with authenticity cert. Sold for just over £50 without it (still good considering I got it in a bundle, so cost me about £1). If signatures can be matched to online sources you might get a decent amount (i.e. if you can identify who signed). If not, it's a shirt someone has drawn on.
Might be better finding someone on this forum who is interested than putting on eBay.