Help making 'selfish' choices (NGO work)

[Gronky]

I've been doing research/analytical work with the same company for almost my entire career and, 5 months ago, was suddenly offered the opportunity to colaborate with an NGO in Central Africa. I took them up on it, expecting some more outdoors time but it ended up being far more physically demanding than anticipated (I'm in my mid 50s) as well as being very sparse on creature comforts.

Since I'd agreed to it, I made no fuss while I was out there but I've only been back for a couple of weeks and they're already gearing up for next year. To be fair to my employer, they've been extremely appreciative towards everyone who took part but it feels a tiny bit like emotional blackmail (since the research portion takes place in tandem with humanitarian work, including disease prevention). This may well be a self-imposed worry but what would be the best way to tell them I want to carry on working in the UK without seeming selfish?

If your strengths are better suited to the UK-based part, can you make a business case for someone else to do the field work and you to do the office part?

They should be recruiting and training someone local anyway.

Thank you very much. A buisness case sounds like a great way to formalise the request so I'm less nervous making it.

MrsTerryPratchett, it's hard to explain without going into a lot more detail but the methods we use aren't really cost-effective for routine screening. I imagine there's already something in place but I'll pass it on to make sure (hopefully, I don't get dragged into that). Thank you.