I have just fitted new front dics calipers and pads to my 2015 skoda roomster 1.2 tsi with 35000 miles the items were replaced as brakes had seized on 1 wheel following a successful mot/nct test a d 1 front disc had been fried so to speak after fitting new brakes and bleeding system all 4 wheels are locked any ideas

It could be that the brake pedal hasn't returned fully. Try and lift it with your toe. Also check reservoir isnt full to the brim. Only other thing I can think of is ABS unit. It may require vcds or similar to bleed if air got in while changing calipers. As its all four wheels I reckon its trapped hydraulic pressure somewhere between master and ABS.

Alasdair