Harry,
Yes, you can elect to remain in the Scheme as a Deferred Member. Everything seems to stay the same except that you have to deal direct with the Trustees in the Isle of Man. Works fine, but there is a small amount of bureaucracy to go through initially for the Trustees to establish your identity. I think there's a description in the FAQ section of the Provident Fund website - which you can continue to access as a Deferred Member after leaving, and use to make Switches.
The only sting in the tail of electing to become a Deferred Member is that for some reason which I never really got to the bottom of, the monthly Employers Contribution (if I recall correctly) due to be paid in each of your last two months as an EK employee will be withheld and paid to you along with the other funds which are retained when you leave.
7B