Insurance and tax would not be a problem as i would insure it for 12 months to my home address and just tax it and sorn it as normal as well.
The only problem i see is the MOT if there was only some way to get around it.
Your insurance as stated is likely to be limited to only so many days a year. If memory serves me right Carole Nash will do longer cover but pretty sure it is not more than 90 days at one stretch.
I moved out to live in Spain earlier this year and brought my Z100SX with me. Wish I had done my home work first, It was going to cost me €670.00 for insurance and to put it on Spanish plates was in excess of €1000.00.
My way to avoid changing the plates was to ride it back to the UK once a year get it MOT'd and ride back, at over 2000 miles return trip a long way to go for an mot.
In the end I sold the bike to a Brit who is riding it around now and running the risk of getting done. The same guy it turns out has no licence and rides like a man with a death wish. I have recently had the confirmation from the DVLA that I am no longer the keeper of this bike.
I ended up buying a new 2010 unreg Fazer 600 S 2 and having fun on that.
To actually think about keeping a bike in central Europe and jumping on a plane when you get cheap flights seems to me personally to be a bit daft, expensive bike /cheap flights?? If I was you I would check out bike rental surely that would be a better option for you?
I do understand where you are coming from seeing as the weather window in the UK is basically 4 months. Be advised that Central Europe gets bloody cold in the winter as well. I had a place in SW France not far from Carcassonne which is less than an hour from the Mediterrian and come winter time it is bloody cold and stays that way from mid October through to mid April. I now live on the Costa Blanca which in the summer is to bloody warm to ride during the day, I am not one of the idiots who will ride a bike in Tee Shirt , shorts and open toed shoes.
Lew