The St Albans MES show is on the last weekend in September, That's 29 & 30th. Bottom right hand corner of the city near the M25 so easy to access and big yellow signs are going up on the road junctions to lead you in (easy to get council permission and proper signs last for ever with just a date change each year)
See **LINK**
Engineering models, boats, Meccano, control line 'planes, home made food, train rides for kids, food, 'have a go' radio controlled boats for kids, food, cars and trucks. Junk ( I mean usefull stuff) stall.