As Richard notes, Airfix produced a Bedford MK in 1:76, along with soft and hard topped Land Rover 109s, a Land Rover 101, a 105 light gun and a Saladin and Saracen. They went out of production a couple of years back but may re-appear one of these days. They still turn up on Ebay from time to time, with prices that reflect their scarcity.
There are a number of small companies that produce post war British soft skin and armoured vehicles in 1:76 and resin including Matador Models http://matadormodels.co.uk/76B PWB/lists PWV page 1.htm , Kingfisher Miniatures http://www.kingfisherminiatures.co.uk/vehicles-1-76-scale-c1.htm and Milicast Models http://www.milicast.com/shop/home.php?cat=14 . Personally I would only buy from the first two of these at shows but I have always found Milicast mail order service to be reliable.
In addition to the Aveling Barford mentioned by Richard, Oxford Diecast have various 1:76 diecasts that can be used as a basis for post war British vehicles, including Land Rovers.
You could also look on eBay for 1:76 white metal and kits by BW Models and 1:76 and 1:72 scale resin kits by Cromwell models, and for out of production kits by Kingfisher and its predecessor CMSC. (Some of the of the BW moulds were bought by Hobby Den in Ireland and they have a few ex BW kits in their list - see http://www.thehobbyden.com/index.php?cPath=57_142&osCsid=mftfktj3f2vd9fta3lag6tgrc2 . Others were bought by Matador and have been incorporated into their own range, but the majority of the BW - and CMSC - range are unfortunately out of production.
In 1:72 both ACE and Takom produce kits of British armour in plastic, including Centurion and Chieftain MBTs and the FV432. Ace also, from memory, have produced kits of the Stalwart, Salamander, Saracen and Saladin. Challengers, Warriors and AS 90s are available from other producers in plastic 1:72., whilst Revell do both and an M109 and a Fuchs NBC variant that can that, with a bit of work , be converted to UK standard. S&M Models also do a 432 in plastic and Dan Taylor has a number of conversion sets for this kit - see https://www.dantaylormodelworks.com/cold-war-75-c.asp which may also fit the Takom kit.
There are probably other kits about, but these are the ones that spring to mind.