I'll try!
Back Neddy each way (NB put £10 in the stake and they'll take £20 - £10 for the win and £10 for the place - the latter pays a quarter what you'd get for the win). The places paid out depend on how many horses, but say they normally pay three places, but this race they're paying four. You lay the £10 win, and separately lay the £10 place. The exchanges have place markets - check Betfair's is the standard 3 places - often they have an extra place market as well. Make sure the matches are close as you would normally.
If Neddy comes in 4th you've won the place part of the bet at the bookies AND both lay bets as he wasn't the winner, not was he placed in the standard 3-places market.
Often several bookies have an extra place on the same race so you can back different horses which increases your chance of one of them coming in the required 4th place.
It's a gamble as you only win when your horse comes 4th, but you should be able to minimise the risk, and if more than one extra place is being paid (eg WH tomorrow) that also means you have a better chance of making money.