We had this on Mk5 when we had one. I tried bleeding it several times and it was marginally better. Reading around at the time, I was led to believe it was a problem with the slave cylinder (apparently they can crack).

No - gave up on the car and sold it, as this was just one of the many problems with it...!

Ah, the hot-start issue!

This is well known and there are 2 possible causes (and only one easy fix!).....

It can be a weak battery that is getting towards the end of it's life - this is the easy fix. We had the hot start issue and replaced the battery and it did make things better BUT it doesn't solve the problem altogether. The other cause seems to be down to the engine control module, specifically the program logic. After reading around, it seems that the 1.9TDI on the Mk5 was programmed to inject slightly less fuel when the engine had only recently been switched off/was above a certain temp - hence takes a bit more turning over to get it started again. I don't know why it was done this way and I recall some Dutch-based tuner was offering a fix to the control module logic to fix it.....so drastic action!