Hi all, just an update, I had purchased a kewtech loopcheck 107, All my electrics seem to be in good condition and wired correctly after all, the green led loop tes led lights on all sockets, according to manual this means the earth loop is lower than 1.8 ohms, the loopcheck has an rcd test feature, on test the rcd did trip so it appears to be working after all, the other way I tested the rcd was using one of the above tricks, I first used the led tv, the second experiment was using a diall 4.7w gu10 led bulb which claimed to be 40ma, (Worst case if the bulb was 40ma, is 40ma flowing through your bodu survivable?) although on the current meter test it was drawing somewhere between 19 and 20 odd milliamps, I temporarly disconnected the neatral then connected earth, so the bulb was connected to live and earth, this tripped the rcd immediately about a second, It appears the rcd does work, As for the rcd appearing more sensitive in the past I can only conclude I must have had an appliance which had a bit of earth leakage but has then been replaced.
I am quite satisfied now that the rcd is working as it would save my life should the worst happen.