"The £5.25 only comes in to affect if we've completed any work and given a confirmed date."
There is no way to find out if you have "completed any work", you give us a date and then cancel at the last minute after we have already booked time off of work.
As mentioned at #2, unlucky customers being messed about by VM during installations will, most likely, have to take their claim to CISAS for arbitration and a decision while VM continues to talk about 'provisional' installation dates. There is no mention of such a thing in the OFCOM minimum standards document.
The whole point of the compensation scheme is to make sure that VM gives a reliable date, when the customer places an order, as to when the service will be installed/activated. A customer may actually make a choice of VM over another provider if VM's offered installation date is much quicker than another provider offering the same services.
If the moveable installation date claim was actually 'a thing' then VM would never have to pay out any compensation as VM could simply just keep moving the installation date forever. From the OFCOM doc
9. Subject to paragraph 40 (exclusions), a Communications Provider must pay automatic compensation to a customer if it does not activate a customer’s fixed line or broadband service by 11.59pm on the date initially confirmed in writing with that customer.
key word being 'initially' and no mention of the word 'provisional'.
VM can mess about with the pre-install dates as they wish as that should not inconvenience the customer too much as it is external work.
VM can also make legitimate deductions for things outside its control (such as waiting for wayleave agreements and council permits) but the deductions are limited exclusively to those sorts of delays. Customers may have to do their own research to find out how long some of these delays are in reality as past topics on here have suggested VM use these too often as a cover-all excuse.
So, the pre-install date to run in the cable might be moved but the initial installation date in writing to install equipment and activate services is fixed. If that fixed date is missed VM has to pay up but may make legitimate deductions for things outside of its control (para 40 from the OFCOM doc).
The above is my take on the processes and requirements. Can't recall any detailed feedback on here from any unlucky customers who have actually gone through the arbitration process and ended up with a good/correct settlement once it had been shown VM's 'interpretation' of the rules was not in line with the OFCOM description of the same thing. Some direct feedback and outcomes from some actual cases would be interesting to hear.