Let's get the easy question out first.
abpan wrote: ↑Fri May 16, 2025 1:26 pm
3. Would there be any impact on the primary applicant's naturalization process?
No, assuming that they meet both absence requirements (over the five year period and the one year period) and the physical presence requirement.
Now let's look at the other questions.
abpan wrote: ↑Fri May 16, 2025 1:26 pm
1. Their application will be withdrawn automatically and IHS charge will be refunded, right? do we need to inform Home Office before leaving?
The application withdrawal should be automatic. That is what the law states. I'm not sure about the IHS refund and I will leave it for others to advise on that point. The application fees of course are lost.
abpan wrote: ↑Fri May 16, 2025 1:26 pm
2. If they apply for a fresh visa in future, would there be any probable impact? would this be treated as overstayed?
They are not treated as overstayed if they either had leave to remain at the time they left the UK or they had Section 3C leave by making an in-time application to extend their leave to remain.
The impact question can get interesting. To the best of my knowledge (and I invite others to correct me if I am wrong on this point), the immigration clocks for your dependents will be reset to zero and essentially they will need to start their immigration journey in the UK back from scratch, with an initial visa application at the British embassy/High Commission and then a new 5 or 10 year (depending on whether the rules are changed as proposed) cycle. The time they have already spent in the UK will not count towards settlement/ILR.
They will of course need to meet the requirements for dependents of a person settled in the UK, which may be different from being a dependent of a Skilled Worker visa (i.e.they may be subject to different rules and requirements). I presume that you earn at least £29,000 per annum, because that is the minimum income requirement you will need to meet. Your spouse will need to meet the English language requirement too, if they don't already meet that.
That should give you some food for thought.
I am not a lawyer or immigration advisor. My statements/comments do not constitute legal advice. E&OE. Please do not PM me for advice.