This matter has been discussed in depth on other trading forums. There are two contrasting views :
(i) men who have been or are presently trading as a profession are able to offer an insight into their expertise,
(ii) the courses are worthless because if the men who were running them were so clever why do they need to teach others ?
The answer lies somewhere in between these two views. As you are out of work I would recommend that you
(i) decide which sports/markets interest you most and which you feel you have particular knowledge of,
(ii) study these markets and their movements as much as you can,
(iii) use a training/test mode initially but move to real money as soon as possible,
(iv) start with the Betfair minimum stake of £ 2. Don't be tempted to use small stakes under the Betfair limit as placing them is subject to considerable delay and this can can unduly influence your trading,
(v) don't spend money on training courses. Instead, use it to trade and learn.
(vi) learn as quickly as you can that it is impossible to have winning trades all the time. You must accept losses as part of the job and move on.