Ok since we are talking comparative value then we should use the average UK house price as a base.
Our constant is £1500 - Launch price in UK of A1000 and suggested launch price of X1000
Average UK house price in 1985 £31000
Average UK house price in 2010 £223000
Therefore an A1000 (£1500) was 4.8% of the average house value in 1985
Whereas an X1000 (£1500) will be 0.67% of the average house value in 2010
So an X1000 today is about 7.2x less expensive than an A1000 in 1985.
I hear VCRs and CD players were relatively expensive when they came out. Computers are a commodity now, how expensive an A1000 was in 1985 is no longer meaningful.