In reply to Gripped:
My normal process for time lapse photography is to open up the sequence in Lightroom, make adjustments (exposure, contrast, white balance, etc) to a single frame and then copy those adjustments over the rest of the sequence.
Once the frames all look good I transfer them into Photoshop, which can be used to auto-align all of the frames if there was any movement (compensates for things like vibration) and then stitch them all together.
The menu options to stitch a sequence together and then export the whole thing as a GIF are a bit buried but there are plenty of tutorials online.
There may be some free software which specialises in creating time lapses but I've been happy with the results from Lightroom and Photoshop. I use Lightroom every week so I can justify the £10 monthly fee for their photography plan.