Hey guys,
Searched, read the stickies and the maintenance sub-forum but cannot find anything specifically related to my problem.
First off, I enjoy driving my GTI but am a bit clueless outside of the basics so go easy

.
I have a MK3 GTI 8v on an N plate. Had it about a year and a half, no mechanical issues, went through last MOT first time with just minor faults. 140k on the clock.
Unfortunate circumstances have meant I have not been able to drive it for 4-5 weeks, but went to start it today and it won't turn over

. It sounds like the starter motor is getting a slight kick, but nothing after that. The electrics work okay (dash lights, electric windows etc) but I am wondering if because of the lack of driving the battery has gone flatish and while there is enough juice left for the windows, there is not enough to turn the motor.
Any advice? Thinking it might be worth replacing the battery (don't have any means to check it) but thought I'd ask the pros in case there were some obvious things I can check or if based on the above description it's not a battery issue.
Cheers!
DMUK