They should get their website booking engine sorted out.
They have recently reduced fares from LCY - when you select an outbound flight from LCY on the website it updates the prices of the inbound flights before you select one (back to LCY) and you should pay approximately the total price of the two flights added together. The website adds on about another £20 to the total sum of outbound and inbound flights. This happens to fares in both economy and business in the summer months.
I called websupport in the week but they still haven't corrected it.