Cheaper alternative to plagron bat mix/royalty mix uk only

Looking to put up in some diecent soil but begrudge paying plagron prices is there any alternatives that are just as good from B&Q or somewhere ?

last i got was from tesco bog standard general purpose comp, i mix it with the tesco low odor low dust kitty litter(pink bag), 20ltr comp 10ltr kitty,you can start at 50% but i build it up over time, its also a good mix for growing most posh plants too, not the cheapest but worth it, just keep recycling it year after year just add neuts when needed
last wk kitty 2 for £7 or £3.50 each
Comp £8 for 2bags ?ltr about 25ltr
pick or sieve the dross out of the cheap stuff... i found a twix wrapper in one bag
hope its useful Enjoy