Travel to russia by car carrying my wifes collection of dolls

Question

Very shortly my wife and I will be driving to Russia from the UK,on a 90 day private invitation visa  the purpose of our visit is for me to submit all documents to the Russian immigration authorities to request residency permission my wife is Russian and has an apartment and dacha in Russia, she has a collection of dolls ( not antiques) but quite a few she has become attached to and wishes to take them  to Russia and when there I will build a cabinet for her collection of dolls at the dacha .they are for personal viewing and the dolls will be staying in Russia when the 90days limit is over and my wife and I will leave Russia to return to the UK .
Do you think I will have problems at the border due to the large number of dolls she wants to take ????  I'm a little worried about how to prove they are our own private possessions as we do not have receipts as they have all been purchased over the years from markets,car boot sales and second hand shops