In addition to the potential tax implications that Steven mentioned ( assume OP paid in €25K - exit tax liability €2,050. Reinvest €27,950 and value grows to €30,000 - another €840.50 liability. If value of the €27,950 dropped on the new plan then the exit tax paid on the old plan won't be added back). Granted, these may be only short-term downsides but they're there if OP couldn't go the full term to wash out the cost by the 0.5% pa saving.
Also, if OP was receiving 101% allocation on original plan it's very likely that the €27,950 would not receive that on a new plan, from the same provider. The 1% isn't a provider cost, but a Government one, and the providers cover it on some plans. That reduces margin so it would be unreasonable to expect that they would pay it again on a value that they've already added it to. There's a note about this on the product profile that intermediaries would have access to but a customer would not see that.
Gerard