Leaking wheel cylinders

[ChrisGadd]

Replaced my brake shoes last weekend and discovered that both rear wheel cylinders are seeping brake fluid and spookily enough both on the same front facing piston. Anyhow I have been quoted £19 each + vat, does this sound expensive and if so can you tell me where to get the same but cheaper.
Oh I forgot to say I've been there with replacement seals on another car of mine and they never did last, so I would recommend replacing the whole thing before any of you say "buy the seals".
I would be interested to find out if anyone has an opinion on why only the front facing piston should go ?

[MickS2]

Replaced mine in January this year, bought them from Halfords, their part no. HWC202, £10.49 each inc VAT

[ChrisGadd]

Thanks for the reply Mick that's saved me a few bob