more of a downgrade TBH 10x zooms are bad as it is but going to a 13.8x zoom .......
i do know zoom lens with a wide range on a budget doesn't give optimum performance, but it's the balance of a general lens i want, performance, quality, build, speed, clarity, zoom all in one.

Doubt you would get £200 for the 18-200, Jessops are selling it for £146.78 and I think the daughter will be getting one this week.
Ultra zooms are going to give you a good range, but probably only an average quality.
Do you really need the extra 50mm the 18-250 will give you ?
I have now learnt to make do with the lenses I have, although it does mean changing them occasionally. I tend to find the 35-105 stays on the camera about 75% of the time, only using the 100-200 for things like football and then the 70-300 when really needed.