SUCKER? by Bufo

The wordplay in each across clue leads to the answer with one letter omitted. When read in clue order these omitted letters provide an instruction that solvers will need to follow in order to be reassured that they have got the correct solution.
1 Such creatures fly backwards to perch (4)
5 Topnotch house in the East End, one you and I are heading for (7)
11 E.g., king is in supermarket getting new gemstone (9)
12 Struggling poly is against introduction of bursaries. That’s not the whole story (6)
13 Sentries keep this within reach (4)
15 Campari’s an ingredient of such recipe cherished by Bantu speakers (8)
16 Girl thus gets first-class return (5)
18 One substance obtained from trees the Spanish eat mainly for starters (5)
20 Cobalt initially found in East Germany enclosed in a limited space (8)
23 Oxhead confronts the Queen twice as champion (8)
24 From this source in French Quarter acquires cocaine (5)
26 Lassie is ultimately cuddled by nursemaid (5)
27 Support schoolmaster after his head becomes more insolent (8)
29 Channel skate finally abandons leaving an eel (4)
30 Ducks experiencing hard famine (6)
31 Parrot – bird (male one) with fancy tail (9)
32 Expanse of open country with small houses (7)
33 Each yobbo initially becomes tranquil (4)
1 It’s hot, very thin pancake filled with large piece of fish (7)
2 Nickums start to irritate politicians (4)
3 It’s a rough form of civil funeral primarily intended to bring about redemption (8)
4 At once climbs after a plant with edible fruits (5)
6 Sharon, possibly, chases victory like England in 1966? (8)
7 Tolerate Ingrid finally going to practise, as of old (5)
8 A. J. Strauss, for example, gets duck with style on making a comeback (6)
9 Maiden flabbergasted minister in an interval of silence (9, 2 words)
10 What caterers provide such as lamb and beef (prime cut) (4)
14 Yvette (the MP) getting worried offers to pool resources (9)
17 Far island in The Shetlands. Yearn to work on needlework here (8)
19 Discover hugging ‘River Island’ coat giving a lot of protection (8)
21 Some lingerie that’s scanty worn by lady up front in a saucy manner (7)
22 Down under, it swims round in Australia eating a lot of fish (6)
25 Maintain Romeo must be kept away from man taking woman out (5)
26 Section right at the back, according to a poet (5)
27 It’s nonsense putting items in photograph album upside-down (4)
28 Beginning to appreciate rising melody in operatic piece (4)

To enter this competition, send your entry as an image or in list format, to before the 8th October 2014. The first correct entry drawn from the hat will receive a book from the Chambers range which has been donated by Chambers.