@croozer you maybe a certain calibre of chap but tbh i really dont think that its a great idea suggesting to someone on open forum to take the action you have done. So perhaps a bit of common sense should come into play.
I would imagine there are a reasonable number of people on site that know someone who knows someone but would not put it out there for the whole world to see, let alone say they would do it!
The problen here is that the female in question has no paperwork, no idea of the Reg No. and left a bike garaged for over two years without any written agreement in place. Does she even have a receipt showing she purchased the bike? From what has been said i doubt it. Therefore she (not her husband) should be seeking legal advice and dealing with the matter once she is aware of her legal status in this matter. Not getting herself or her husband and/or friends into a whole heap of trouble with the police because they 'got even'!
You say to seize back your own property is "simply not an option", well, I disagree.
Who said anything about getting into trouble? If no threats of violence are made and you take your own video footage to dispute any such claim, there is nothing to get into trouble for. The 'heavies' are there to simply to prevent any violence starting whilst the property is being removed.
Opinions were asked for and opinions have been given, what action is actually taken is no concern of mine.
I am not giving instructions to anyone, just as you are not giving expert legal advice......
If he gives you an invoice
for 'storage' of your wife's bike BEFORE any money changes hands, then surely that is tantamount to
admitting that the bike is hers, regardless of his saying that the bike belongs to him after storing it for X amount of time.
sell the bike to the biggest meanest biker you can find' give him a receipt for £1.I,m sure your wifes ex will gladly give him the bike. Ok you lose the bike but you can laugh over a pint.