I share your anxiety a little. We have sent money out to Spain recently to support our residency application in July.
We intend on buying somewhere over the next month or so and will also be at the mercy of the markets as we send more over.
In terms of denominating your pension into EUR doesn't the old saying buy low sell high - strikes me that if you did decide to do this it might make sense to do it on better terms gbp/eur wise.
So many decisions to get wrong :)