My first speedway meeting was also at Plough Lane - 2 friends from college (one a Hull fan, t'other from Exeter) persuaded me to go along with them to the "Southern Riders Championship Final" in (I think) 1976, or thereabouts.
I was hooked from Race 1! I'm pretty sure that I still have the programme somewhere (probably at my parents' home), but if anyone wants to remind me of the details .....
While living in London I frequently visited Wimbledon, Hackney, Rye House, Canterbury, Crayford, Eastbourne and (especially) Milton Keynes; when I moved up to Northampton in '82, my haunts changed to MK, Peterborough, Coventry and Oxford.
I rose to the dizzy heights of chairman of the MK Speedway Supporters Association for 12 months, as well as running a fan club for Steve Payne, and often helping out as pusher/flag-waver/pit crew at Elfield Park when it was Bob Humphreys' training track.
Nowadays? I'm sorry to say that I don't visit speedway as often as I should ... Why? The increased cost of watching ... being out of touch with the names of modern riders ... being unimpressed by the attempts of modern 'promoters' to push this wonderful sport forwards (it says something when you hear a steward say "I pity anyone who paid to watch this crap"!). But I still prefer the 'lower' racing leagues (much as NL was always better than BL) for a better standard of RACING.