Agreed that any increase is likely to be slow when ecb starts to increase rates. On the when front they've pretty much said this won't be before this time next year. However, given how signposted the ECB has been about this you would expect longer-term rates to to tick up in advance of this. On the how much front I would have thought very slow. It's almost a symbolic gesture too mark the end of the crisis. However, European growth (at present) is still fragile. They won't want to damage that.
What really matters for us is how banks react to all this. I'd be surprised if much happens on the variable rate front before the ECB starts to raise rates. Almost all banks existing book is variable. The new business a lower variable rate would attract is likely to be nowhere near what they would lose in their existing loans. I would expect banks to absorb the first couple of rate increases given their current healthy variable rate margins. Put simply on thet PR front it's will be a lot easier for them to say they've taken some pain with the first few increases now it's borrowers time.
As for fixed rates where there has been some movement (dare I say competition) recently I would expect banks to eek out as much as they can. This is where a lot of new business had been transacted. The ability to differentiate between maturities means they can sign post increases if they want to (kind of like how all the budget details are leaked well in advance - by the time the pain comes you've been expecting it).
Based on all that I would (and have) followed others advice of picking the best mix of fixed rates versus overpayment options. I plan to review in September and see if it's worth incrementally breaking and refixing