Alert:
One of the consequences of Britain's vote for Brexit has been a significant (currently 13.3%) devaluation of the Pound vs the US Dollar. Most component parts are sourced and priced in US Dollars. Just prior to Brexit in June, the Pound reached a high of £ 1= $ 1.50 but is currently trading at £ 1 = $ 1.298, or 13.3% lower.
A phone costing £ 450 prior to Brexit based on the £/$ exchange rate now, simply put, should be priced at £ 510 today and a phone costing £ 500 prior to Brexit should be priced today at £ 566.
Sorry to say but to hope that the cost of the new Pixel would ever be priced here at £ 400 or £ 450 is, sadly, out of touch with the weakness of the Pound.
You may recall that when Apple released the new iPhone in the UK recently, they cited the Pound weakness as a reason for their price increase here.