Where in Europe are you?
I see nothing wrong with your plans. Why not do the renewal in a tailwheel and have some fun, you are allowed to enjoy yourself you know. Wherever you chose to do some/most of your training you will have to be assessed for training and then signed off by an EASA ATO/DTO. They will certainly require you to do at least some flying with them, so speak to them first. Then you must do the renewal test with an EASA examiner appointed/approved by the state who have issued your current licence.
The simplest way is to renew your SEPL at a local ATO/DTO in whatever aeroplane they use and have the SEPL re-issued first. Tailwheel is not a rating but is called "differences" and although this must be done with an EASA Flight Instructor (for your EASA licence) in the first instance it is not required to be done at an ATO/DTO and therefore no national authority administration is part of it - a simple sign off by the instructor suffices.