Landing a job in 2 months of arrival in UK is very very good! If you trace back in this section of the forum, you will see success stories where people have taken anywhere between 4 to 6 months to land a job. There are also people who have had to wait longer.
So I would consider you really lucky and good at what you do to land something within 2 months. Considering you have already had 5 years of prior UK experience it will only be an advantage for your next job search.
Having an Indian number in your profile and floating your profile in the UK market will clearly not get you any calls, as recruitment agents, are more interested in candidates who are available immediately for an interview, and clearly they don't want to go to an employer with your profile and tell them, candidate is in India, but is available for telephonic interview. They might perhaps do that, if it's a niche skill, and they are unable to find local resources to fill that gap. I would really advice you to get to the UK and start applying.
Not having specific domain experience is not an issue. Having worked on multiple areas, with the core skill as C++ and application development prior to Project Management, is quite good, it doesn't tie you down to 1 domain, and having varied skills is an advantage to be able to manage projects be it any domain. I have friends who are core technical application development guys, who move between insurance, banking, and health care domains quite easily. If you have worked with some big brand names / services companies / product companies, that will add a tad bit to your advantage of getting noticed and get you interview calls.
There are project management roles that require, huge amount of coordination and tracking of tasks, good verbal and written communication skills, to be able to communicate to people at all levels, strategising and planning with stake holders, and these skills aren't easy either.
I am a techie and work in a core product engineering company, where we don't have a dedicated project manager, and it is getting increasingly difficult with individual group heads (Product Management Leads / Multiple Development team Leads / Test team Leads / Documentation team Leads ) managing their own tasks, and reporting into an Engineering manager. But there is no project manager to collectively track and manage tasks of independent teams working on a single project.
This has been identified and we are aware we need a project manager, and we are trying to find a resource internally, as to who that potential project manager could be. (Unfortunately, recruitment budget for the year is up, so not recruiting externally for now)
I don't know your personal circumstances, so can't comment, but all I am trying to do here is just trying to encourage you to keep a more open mindset and try and persevere a bit more.
Lastly, age is not a problem at all, at least here in the UK. People don't even mention their age in their resumes, and HR don't even ask.(If I am not wrong, legally they are not allowed to ask for age/sex/sexual orientation/race) What matters is your prior experience and confidence and ability to take tasks through to completion. We have just had a software engineer Intern who has joined us recently, as part of her final year masters program, and guess what, she has two boys aged 16 and 9.
Don't constrain yourself with limitations that people and yourself have planted in your mind. Explore more, be more confident in yourself, and am sure something will open up.
Good luck.