Without knowing how many hours it has done, it's difficult to value it. £48K is at the high end for a Eurostar that's done average hours for coming up to ten years.
Whether or not it's registered as a Microlight should have no bearing on the price.
The group monthly subs and hourly cost are a consideration. Oop ere the EV-97 can be flown for £20 a month and £60 per hr wet, with no Capital outlay.
To put things into perspective. A decent Jodel can be bought for less than the price of two of your Eurostar shares, with similar running costs and better performance.