A travelling/flights question i need help with please!!?

I think sticking to one area is a better idea than a round-the-world single trip, and southeast Asia is supposed to be an amazing place for travelling. India, Thailand and Malaysia are all good choices, I would also include Cambodia on that list (include a visit to the capital Phnom Penh and ancient ruins of Angkor Wat) but byp Sri Lanka (probably the least stable and safe country out of all those). Vietnam may be a hidden gem, so look into spending a week there too. I can't really help with prices etc because I'm not sure if you have agencies in the UK that might offer package deals, which would include all your flights for hopping from one country to another. Good luck though, enjoy the trip.