I had mine installed by a Schneider subcontractor last week. He was very helpful although it did take a full day which I wasn't anticipating.
Ours would be classed as a non-standard install - it required 2 walls to be drilled through but the subcontractor did not charge any extra for this.
Unfortunately we had a few issues. Namely our fuse box (and I say fuse box because it's the old style box) did not have spare capacity for a 30 AMP connection - and even if it had, the gauge of wire would not have fit! That meant we needed an additional consumer unit which was an extra £180 to install. Not too bad as consumer box installs are normally around £350 around here, but then again it is only a small one.
Along with this, our earth connection for the mains water needed upgrading to 10mm as the existing was only 6mm - which doesn't meet the new regulations. Luckily our mains water feed is only 1 room away from the fuse box so this wasn't
too bad (although has left us with some redecorating).
As we don't plan on charging the vehicle in the garage and our garage door is metal that also needed grounding which wasn't quite as big a task because the wall box is right next to the garage door.
There was an extra £240 worth of work/materials on top of the £315. So that's £555. Reading through the governments guidelines it says the grant will cover associated work, so I was pretty sure this would be covered. As it turns out a standard install is £1020 plus £240 for the OLEV meter, @75% that's £315. Phoned up Schneider and they agreed to add the work to their bill so it would be covered under the grant. Unfortunately the grant is capped at £1000 so our install ended up costing £500. Still, better than £555.
So if you have any additional costs (probably not up to £6k, I'd cancel at that point
) it's worth phoning Schneider whilst the electrician is still at your house.
Oh and we're now also waiting for the DNO (distribution network operator) to come out and fit an isolator switch so the electrician can come back and do the final connections and test. It should be free, but it's not ideal - especially if my order hadn't been delayed. Schneider should send people out for surveys before the electrician gets here.