Over the years Flybe Engineering at Exeter have repaired many corroded wings on 146 family aircraft - both in their own fleet and those of third parties. I'd imagine that they could well be world leaders in this role!
I should also think that Flybe would have no worries about the level of corrosion in these RJ aircraft. Repair is cheaper than buying a new aircraft! I understand that engineers have visted Turkey and have conducted some corrosion repair on-site.