I don't see the problem at all. We offer a range of universal benefits to our pensioners,such as a free bus pass, free TV Licence, cold winter payments etc., and for a lot of pensioners, these are undoubtedly valuable and welcome perks. For some pensioners, these benefits are potentially essential.
There are however an awful lot of pensioners for whom these benefits are meaningless - and of those, many would not begrudge the loss of them atg all.
We keep being told we are in an age of austerity, that we are spending too much of the tax take on benefits - welfare, pensions, NHS, etcetc. We also keep being told by the Government that we are "all in it together". So, if you can find a threshold above which such free benefits are not applicable, that seems fine to me.
The big problem is how to implement such a system. The reason such benefits are administered as universal benefits is in a large part due to the setup and associated administration cost of implementing a targeted benefits system and the vetting that would be needed.
We now have an estimated 10 million of our 60 odd million population over 65. The cost of free bus passes and winter fuel allowances free TV licences etc. must run into the £billions each year, so it is certainly an area worth looking at.