At most tables, East opened four clubs with the eight card suit, South and West passed, North doubled and South bid four spades.  Despite holding 21 points, North felt that, with only three card trump support and South not necessarily having many values, it was too dangerous to bid on.  A couple of tables in the top division did bid six spades, but one went down presumably taking the spade finesse after a club lead, whereas Catherine Curtis played a top spade first and made the contract.

At the table where I was watching Colin Simpson chose to open five clubs.  Tony Forrester, sitting North, doubled and David Gold sensibly decided to take the penalty rather than bid a speculative five spades.  They defended accurately taking six tricks including the heart ruff and that scored 800.

Note that six diamonds is an excellent contract, but this proved impossible to find after the opening pre-empt.

As Freddie Illingworth pointed out, opening five clubs was probably not a good idea with two outside queens, likely to be useful for defence, but having no great trick taking potential.