The trouble about Minis, is they aren't "expensive" markers, so people will not pay what you have put into it. What you have done, is carry out a labour of love and due to that you will never get what you will want for it - or even close
The anno and lazering will add nothing to the value
- all it will do is make someone look at your marker over someone elses... end of the day, it comes down to price
So take that off, the marker would be £120 + approx £220 in actual upgrades (not inc the ones you can't remember how much you paid). So that is £340. Now, knock off a chunk for a realistic price of 25% off that price leaves £255... and then it would take someone who'd really want it to buy it (which at that price, nuts not to).
I know, not what you want to hear