A friend of yours owns a shop selling CDs and posters for the 12- to 14-year-old market.

From the following information advise him on the potential problems that may be encountered in the valuation of such items for balance sheet purposes:

(a) greatest hits compilation CDs have sold consistently over the months and cost £5,000 with a retail value of £7,000

(b) sales of specific group CDs, which ceased recording in the previous year, have now dropped off to zero and cost £500 with a total retail value of £700

(c) specific c band CDs, which are still constantly recorded and selling in the shop every week cost

£1,000 with a total retail value of £1,400

(d) specific c artist posters are currently not selling at all (although CDs are), and cost £50 with a retail value of £100.