Thank you all TI-ers for replying and for your very detailed suggestions.
I am going to continue with short stroke drills as you all suggest and pay attention to balance. I noticed after my ankle injury that as I started to use my feet again that I actually felt more comfortable without the feet (with legs trailing in the water) and I am now wondering whether my problems are also related to timing the kick properly.
I am 5 foot 6 inches and so I do not know if I can manage the 12-14 SPL that you have mentioned as a target. At the moment, I'd love to break the 18 barrier which I have only crossed once and achieve 15-18 consistently. I still fluctuate between 20-21 for a 25 metre pool.
I can't find a tempo trainer in Singapore but I can try to increase my stroke rate. What i find is that as I increase the stroke rate, my SPL go up too. So I can comfortably swim a 32 sec lap but at the cost of pushing the SPL to about 25 rather than 20-21.
I'll see if I can get a video up one day. I would very much appreciate all your expertise. I try hard but it's difficult to correct things when you train alone.
Thank you all once again,