Some good points made already. I would add the following for you to think about:
Getting your licence is about more than having lessons and passing the skills test. You also learn to navigate around the local area and get to know some very experienced people at your airfield who will be helpful to you long after you get your licence. Also at your friendly local club you may be offered the occasional spare seat by other pilots - watching and learning from the passenger seat all adds to your experience.
Also, my experience of UK schools is that they are incredibly supportive in getting you through the exams with the minimum of stress and effort.
Looking at it from a flying club's perspective - if you have spent £5k learning with them they will give you a warmer welcome than if you turn up with your overseas acquired PPL.
I thought about learning abroad but decided to persevere with the UK weather. I was fortunate in that I could schedule a lesson every day (either first in the morning or late afternoon) and averaged about three lessons a week between February and April.
If you start having evening lessons after work you could make substantial progress. Otherwise could you book half day holidays that you don't take if the weather is unfavourable?
As FFF says, cost of flights, eating out and accommodation can erode the saving that you make learning abroad.
Hope this helps
Springers