Going abroad for periods under six months is fine but be aware you need to at least be contactable through emails throughout to keep your application live.
Be aware that vising some countries can affect your security clearance and check the FCO website to ensure you aren't visiting areas advised against.
Generally European, Commonwealth countries and the US are not an issue, but countries that do not have strong diplomatic links and security protocols aligned with UK can significantly affect timelines for processing security clearance.
It all sounds very cloak and dagger but we have a history of attracting individuals who have attended terrorist training camps overseas, committed serious crimes overseas, fought as independent mercenaries and some who have worked for overseas government agencies.
Not so long ago we had a guy wanted for several counts of attempted murder overseas, another was caught smuggling in several thousand quid in counterfeit banknotes, so the security people can get a bit twitchy about that kind of stuff, for some reason.