I did my CPL in the UK part time (had to hold down a day job Monday to Friday) at a UK FTO. I was also doing an FI(A) course in parallel at the same FTO, and despite UK weather - it took around 5 months to get them both done. I did my IR in Spain for 3 reasons (1) could only train at weekends, (2) didn't want the course to run over many months (would have missed too much weekend flying in UK as instructor), (3) good flying weather in Spain is virtually guaranteed all year. The IR took 6 weekends & 3 weeks of my holiday allowance to complete.
Hope that helps.