We have plenty of mothballed ships that we could refurbish and sell India in the interium. Meanwhile, we can work closely between India and Britain to modernize India's armed forces and get them up to NATO standards.
India is already buying mothballed ships from Russia(mid size carrier) & the US(amphibious assault vessel),but these stealth frigates are longterm investments.Most of the ships which the US or UK may offer for sale are of the late 80s vintage which will be as cheap as newly built Russian equipment with NATO compatible equipment(which Russian manufacturers actually offer.