Every time I stay at the Ariel they mess up on the points postings - watch this, almost every stay over the last 5 years (2 plus stays a year) they take the room rate before VAT and then subtract VAT from this amount even though it is on top of the room rate. Then they often add extra charges for phone calls that I do not make, or minibar charges for free platinum items in the exec rooms.
The Ariel used to give free parking and a welcome drink to Plat's but this stopped last year, and no points for the daily parking either. And they explain this "enhancement" as keeping in line with the competition around Heathrow.
I only continue to stay here because of the low rates and also ease of getting to/from the airport on the free bus transportation to the airport.